Thankfully, I only know the answer for Oyster card or I’d be writing all night:)

No ID required. You buy from a machine.

18) Bonus query: this grocery chain 'Sainsburys', could someone comment on it? Canucks, how does it compare with Loblaws?

When I lived and shopped there, Sainsbury's seemed like a Safeway (US supermarket chain) to me, stocked for British shoppers. That was a loooong time ago. If you're from Canada, the comparison may not help you.

In London, I usually went to Waitrose: oh, for a Waitrose ready-made prawn mayonnaise sandwich to eat on the steps of Covent Garden at lunchtime!

The answer to #1 is no. The answer to #17 is why not try it?

It's not just a cliché that it all depends on where you're coming from / your perspective --
given the tenor of your first few questions, I think you're going to need to hunt a bit to find the better quality options.
I'm thinking of Whole Foods and Safeway -- what do you think CWSocial means when she compares Sainsbury's to Safeway?
What do you mean by same quality as Whole Foods? Here in SF, Whole Foods realized after a year or two that it was a step down from the local standard and started offering more local products and signing them as such,
while in other places in the USA the Whole Foods brands are a step up from what they have locally.
I still feel like I'm being fooled when I buy cheeses from the Whole Foods supply chain, because it's almost always insipid compared to what local grocers sell as standard. I'm saying that it you want to get good fresh high-quality produce and cooking in London you will have to do some detective work, it won't do to just pop into whatever comes along as you wander about.
People keep protesting (too much) that London is now a foodie destination, and that's kinda sorta true, but the microwaved plastic-wrapped apple sandwich doesn't fall far from the tree.

Point of Clarification: the few Whole Foods here in Toronto offer Grade A/Best-Quality Fruit as a rule. There are very few other better retail options for the shopper, when it comes to fruit. Understand, I am not a huge fanboy of WF, its just that for us, they are nearly the gold standard in that regard.
I am done. the papaya

Good clarification.

Do you listen to British shows, like the BBC Friday Night Comedy?
In the UK, Waitrose is considered fru-fru and chi-chi and other repetitive onomatopoeia
by the average consumer -- fancy coffee drinks and avocado toast are available, but sniffed at (if not poo-poohed)
That's the context -- the situation in SF is that being served tea using teabags is a little bit lowbrow. Loose is expected,
and if the teabag is Lipton rather than some clever aspirational brand and isn't meant ironically or retro-, then that spot is not going to last long. So if that's where one is coming from, all this hand-waving about London being past the post-war brown-sauce stage of culinary development is only really true in select spots, not generally overall. (I'm thinking of the snack shops near the Cutty Sark and chatting with the staff about how none of them had any fresh fruit on offer.)

I couldn't resist checking up on the Cutty Sark and see that there's now a Nando's and a Pret there,
which I suppose is a step forward from Pizza Express. So consider me an ill-informed elitist.

Been to Wilton’s twice, both times for Christmas pantos. Yes, worth going to a concert there.

Question 6) Changes in legistlation over the years have meant that circuses can no longer have exotic animal acts, but at Piccadilly circus you will no doubt see more than your fair share of clowns.

The late comedian Alan Coren commented that the only reason Sainsbury's exists was to keep the riffraff out of Waitrose. (it's just a mid range supermarkert- I do a lot of my monthly shopping there based on convenience of location)

Having worked in London for years, I feel like I have never been there.

1). No
2). The Courtauld is open according to a Google search.
3). Never been.
4). Not been for years. Colombia Road flower market is good on a Sunday morning.
5). Why not Whole Foods? There are several branches in London if you want over priced stuff. There isn’t much to chose in quality between all the supermarkets, except Waitrose will be more expensive.
6). Not when I last walked through there. It comes from the Latin circulus meaning circle, as it used to be a roundabout. I hated Latin at school.
7). No idea what JanisJ or MacDog is. Barrafina is a small chain of tapas restaurants in London. Check their website for their expansion plans.
8). Never use.
9). The scaffold on the Elizabeth Tower is on its way down. Can’t think of other attractions under scaffolding.
10). I don’t buy rare books.
11). It depends on your tastes. If you like Versace, then you may find it ‘outstanding’. Bling bling.
12). No
15). Never heard of him. I have heard of Rush.
16). There probably isn’t that much honey produced in London. Never tried this brand.
18). Never heard of Loblaws. Sainsbury’s is a middle of the road supermarket chain. More expensive generally than Tesco, but the quality isn’t any better. I have switched to shopping at Aldi where possible.
19). Do you mean Marylebone? Either MARRY-le-bun or Marry-le-BONE will suffice.

In the UK, Waitrose is considered fru-fru and chi-chi and other repetitive onomatopoeia
by the average consumer -- fancy coffee drinks and avocado toast are available, but sniffed at (if not poo-poohed)

Hahahahahhaaha

6) Only believed by foreign students.

13) Probably subject to an investigation by the Metropolitan Police and thus sub judice. We’ll just have to wait to see what they say…..

18) “To keep the riff-raff out of Waitrose”. Aw Hell, I went to Sainsburys yesterday…… (very poor selection of nuts imho).

18 - Not that it matters, Loblaw is Canada's largest supermarket chain and also owns the largest set of pharmacies. Sainsburys would probably stand a little bit up-market. Until a few months ago, the Loblaw corporate empire included Selfridges. And since we are showing off our command of irrelevant trivialities, Canadian musician Geddy Lee once owned season's tickets to the Montreal Expos, now playing as the Washington Nationals (to my and Geddy's regret.)

14) The answer, as always, is 42.

The Cutty Sark is not in London.

1) No. But why not just go contactless, either card or Apple/Samsung/Google Pay and save the purchase of the Oyster?
2) dunno
3) fabulous reputation. I've not yet been for a performance but have vetted them for a venue.
4) nope - don't believe in MUST-anything
5) I know of nothing about Whole Foods except I ran like cat with its tail on fire when I saw the prices. Try any neighbourhood Fruit and Veg shop, Waitrose, and if you are near Sloane Square there's the best food store in the West End, my personal fav, Partridges. If near Lords Cricket Ground or Abbey Road Zebra Crossing there is Panzers on Circus Road at Finchley Road in St Johns Wood. Has the best fruit and veg for miles, prices have shot up (more???) since the sellout and refit a few years ago. Try anything at the deli counter and take out some of the best Challah this side of heaven.
6) Too touristy, I avoid going there. Too close to Whitehall. And too close to that little lane named after the founder of Downing College, Cambridge.
7) que?
8) 20 years ago I used to get artist supplies for my father at a small place in or near Wigmore Street, somewhat near John Bell & Croyden. Don't remember the name. Why? Because it had excellent product and it made my father happy. I miss him.
9) dunno
10) what's a book?
11) yeah pretty good to excellent
12) nope

14) redacted - ask the Met
15) nope
16) nope
17) there is an adoption of non-binary in London and the UK - don't sweat it

18) Above or under Tesco depending on where. Under Waitrose. Above or equal with Morrisons depending on where.
19) see Jennifer's answer

20) no thanks

A Big Ben-sized merci to all, for wading through such a BIG list of unusual questions. Much appreciated. I have learned things, thx to you lot. Fair Disclosure: we've sold all of the responses here on this Rick Steves post, to Dr. Alec du Grabertitz of Cambridge. His team is apparently studying 'the impact of omicron on travel forum behaviours'. Something also in his Appendix about 'the response to humour'. Anyway, his payment to us was generous enough to cover the entire trip. Again, we thank you.

Our rental is just off Brick lane. Last time we was in the UK= 35 years ago. We're excited about this spring trip.
Fun fact God's sense of humour: the very first pair of rentals that we looked into, turned out to both have unique backgrounds. The first was the original home of Guy Ritchie, where he invited Madonna to live with him. The second was the site of one of Jack the Ripper's infamous murders. We'd had no idea about these remarkable facts.

Btw, Borough market has been near the top of our list for some time, I just forgot to mention it in that 4th query about food market stalls. Maybe I could've used the word 'recommended' instead of 'must'. The latter seems to promote snark in some. Also looking forward to shopping at Herne Hill plus Broadway markets. This is the part where one of you Londoners goes, "Cor Blimey GL! *Herne Hill!! You are such a thorough travel researcher!"

Gotta go now gov'. The 'London Unplugged' DVD has finally arrived at our local library.
cheerz
I am done. the ned

10: I believe that primary sources are the best. I'd visit Midsomer, Kembleford, Grantchester or Oxford and speak with the locals.

19:

Simply type into your search bar "How to pronounce Marlyebone". I'd be interested to know from the locals if this is really a good pronunciation or not.

19). Do you mean Marylebone? Either MARRY-le-bun or Marry-le-BONE will suffice.

Is the y in ”Marry” actually pronounced? My UK work colleagues always said it more like ”Marr-le-bone”

I think the fruit and veg at M&S is v slightly better than that at Waitrose, but there’s not much in it. The size and scope of the shop is the key…the Waitrose in John Lewis Oxford Street has interesting things I’ve not seen elsewhere; bubbleberries for example. Also the flagship Marks (Marble Arch) has a lovely variety of offerings.

As probably the most local to Marylebone (I live a 10 min walk away) I’ve heard a variety of pronunciations, including the bus lady’s, but mostly it’s something like Mar li bun. But quick and all mashed together. That said, we’ll know what you mean.

Had a very good falafel in Petticoat Lane. Was walking about, looked good, so I bought one.

In Spitalfieds after purchasing Christmas cards remember trying a “ burrito.” Not exactly like the burritos you’ll find in LA but tasty and filling enough to keep me happy!

My UK work colleagues always said it more like ”Marr-le-bone”

That's how I've always pronounced it however being born and raised in Portsmouth with its Cockneyesque accent I may be pronouncing it differently to how other Londoners would.

The majority of British supermarkets offer an own brand 'superior' label such as Tesco's 'Finest', Sainsbury's 'Taste The Difference', Waitrose's 'No. 1' and so on. Most fruit and veg in any of these ranges is generally better than the average and probably better than what is available in Whole Foods which I've found to be anything nothing special other than exorbitant prices.

Honey produced in London is increasing in popularity usually accompanied by the overused phrase 'Artisan'. I've tried some of this acclaimed honey at an expensive London restaurant and I can't say I noticed much difference. Personally I would prefer to eat honey that has been produced by bees that gather nectar from flowers that aren't contaminated by the levels of pollution found in places like London.

(17) My father was an actuary, and whenever he was asked an "either or" question, he would always answer "yes" or "no".

Pronunouncing the L in Marylebone used to be considered completely incorrect, hence it being something along the lines of "Marry-bun". This seems to have died out largely by people being pulled by the spelling. L still not pronounced in Holborn though.

I live in Marylebone, on Marylebone Lane, just off Marylebone High Street, so I’d say I’m quite familiar with the word and its various pronunciations…I say “Mar-le-bone,” and pronounce the “le” like the French article, not like “lee.” I’d say I hear that pronunciation and “mare-eh-le-bone” (again, less of that “ee” sound that you’d get in “marry”) most. But as others have said and as this conversation proves, there is no confident consensus.