Another Day Tour Provider, not Viator.

Getyourguide.com

We've also had recent luck with Tiqets.

Toursbylocals is hit or miss.

When I'm going to a specific place, I often google for local agencies and check out the reviews. They sometimes have more availability and will even add tours if they get participants.

Viator does not provide tours. They are a third-party reseller of tours, so it's not a surprise that many independent companies are all available through Viator. The independent operators give a cut of their fee to Viator for the service of referring people to them. And it's purposefully difficult to identify who operates the actual tour, because Viator doesnt want you to cut a deal directly with the operator and not get their cut.

Its not evil, its just a service.

RS always mentions local tour operators and guides in the guidebooks covering London. You don't mention where you would like to visit - there are many day trips out of London that you can do on your own using train or bus; others, such as Stonehenge, are more difficult without booking a tour or guide. You might also search this forum for past mentions - but maybe those are the ones you've already tried.

I’m not 100 percent sure Viator is not evil. Last year I know several people who went to Europe on vacation and booked tours via this service. The night before almost everyone of them received a phone call or email “ Oh we’re sorry we can’t actually deliver, but we, so here’s a refund. “ Well if you’re tour is something you can’t rebook easy on your own the next day being sorry and telling you it’s cancelled less than eight hours before the tour doesn’t do a thing.

I don't know where you're planning to go, but I took a tour with Evan Evans tours out of Victoria Station several years ago and enjoyed it.

Where are you going? Tours from a large city to outlying sites aren't really a thing i Europe. They do exist, but the target audience is mostly North American tourists. Europeans will in most cases travel to wherever they are going on their own and take a tour once they are there. With a good network of trains and buses it is usually easier and gives you more flexibility.

from London to outlying sites

which outlying sites are you trying to see?

I se Get Your Guide all the time - similar broker nature to Viator but I have always found their engine a bit easier to use. Do PM if you need a specific link and would be more than happy to dig one out

touristbylocals requires you to organize the group for the tour. Never use them for that reason.

We have used Viator when we couldn't come up with a local tour company. Never had a problem with their tours. In fact, I have found when comparing tours that their prices are usually not much different from tours that you book direct.

Spaindaytours is a good tour company for Spanish cities and they accommodate groups from cruise ships.

You might try looking at Rabbies Tours. Just one example here of what they offer.

https://www.rabbies.com/en/england-tours/from-london/day-tours/oxford-traditional-cotswold-villages-day-tour

Small minibus; not a huge bus like other tour companies with 30 or 40 people on them.

I was not providing info on where we wanted go. Just being general. But for example if I looked up Day Trip to Leeds Castle/Cliffs of Dover/Canterbury and supply a date. It comes back booked. Same thing for Oxford/Stratford upon Avon/Warwick Castle. Again, booked. The surprising thing it is 5 weeks out. All of my searches get tied into Viator. Same thing for couple more. So, can't believe there is only this one agency to book Day Trips. There are probably many trips every day to these sights. But by Who? I can almost guarantee if you Google a day trip to any of these popular places you will end up at Viator. Reminds me of doing a genealogy search,, You will end up tied into Ancestry.com. Maybe I am doing something very basic wrong? No matter where you go, there you are!

the tour you want is available almost every day next month on the Evan Evans website. Try there. They have A LOT of various options!

The reason you are getting Viator is they PAID to be at the top of your search results.

I don’t know what search terms you are using, but I searched for “Warwick Castle Stratford on Avon tours” and one of the results was from Tours by Locals. Their tour is available Jun 8, 9, and 10 ( all 5 weeks from now) but dates after that are booked solid for a week.

https://www.toursbylocals.com/TBL/WebObjects/ToursByLocals.woa/1/wa/lookup?currency=USD&wosid=abZbtAA1otMsB4CBd5ORZ0&book=yes&rm=1&day=8&calendar=no&url=Stratford-upon-Avon-Warwick-Castle

Get Your Guide has tours of Stratford, Oxford, Cotswolds ( drive through) and Warwick CStle every day in June from what I can see on the calendar.

https://www.getyourguide.com/london-l57/london-oxford-stratford-cotswolds-and-warwick-day-trip-t965/

Evan Evans has already been mentioned so I did not check there.

hey hey Den
withlocals.com
search either london day trips
search stratsford upon avon
wowcher.co.uk
register for free and see all the offers, many 2 for 1. under travel click spas & country houses. may have special for an overnight, may find another area to spend that night at a nice manor hotel to see place different
driverguidetours.com
look under tours, full day, 10 hours has stratford-upon-avon
aladyinlondon.com
she writes a blog about people, places and things. search: stratford upon the avon
also check out her day trips from london on the train
beenthere-donethat.org.uk
lots of info about UK
getyorguide.com
has been mentioned. i've used them 4X with no problems/issues. some tour companies didn't make it thru pandemic and other are trying to catch up to what they have lost.
visitlondon.com
day trips
enjoy your trip to london, we loved it
aloha

There are probably many trips every day to these sights.

There are, you can find many options at www.nationalrail.co.uk

You folks saved the day! Got 2 tours booked already. THANKS.

hey hey Den
you are welcome. happy for you to check out tours available and booked 2 of them. that takes a load off your mind for things to do and see, hope it all works out for you. please do come back and give us some feedback for others to do research
aloha