We did a London Walks tour of Westminster Abbey and were very happy.
We did not have to wait in line to get tickets, or to enter; the guide
gave us wonderful information on all the chapels and locations of
famous people; and we did not get the sense of being lost in the
crowd. I highly recommend London Walks for Westminster Abbey.
I also did the London Walks Westminster Abbey tour, in October 2015, and was very pleased with it. I got much more out of it than I would have gleaned from walking around with a recorded audiotour in my ear. Obviously, YMMV.
Thanks to everyone for the help! Do I need to get tickets in advance
for the Westminster Abbey Walk or do we just show up at the meeting
place... Also does it cost more on top of that to get into the Abbey
or is that included in the walking tour?
No advance booking with London Walks. You show up at the appointed meeting place and hand the total amount to the London Walks tour guide. In this case they will have (at least) two of them. The amount includes your guide's fee plus the cost of admission to the Abbey - but since it's a discounted group admission the total is still IMO a good deal.
What happened next with us - and I assume that's how they always do it - is that one of the guides scurried over to the Abbey to buy the tickets and the other one escorted the group at a less rapid pace the short distance across a few streets and around to the guided tour entrance of the Abbey. By the time we got there we got sorted into a couple of groups, the other guide appeared with our tix, and we went in. I don't recall going through a security check but I assume we did, and I also assume everyone will continue to do so these days.
We were divided up into I think two groups, one per guide, and I didn't feel that our group was too large. There was actually so much info imparted by our guide that I hope to do this tour again in October because I didn't retain enough of it. (Well, also I had a tricky hip joint that started paining me halfway through and that was distracting.)
Finally, at the end of the organized tour, our guide gave us a great tip. She pointed out where the loos were in the Abbey or thereabouts. More importantly, at least to me, she then told us about the Methodist Central Hall, a large building across the road from the Abbey. Where they have nice, clean loos, free of charge (!), in the basement. Also in the basement is the airy, large, clean and reasonably priced Wesley's Cafe. Hot meals and snacks, cafeteria style, I think even good free wifi. I had a very pleasant lunch there and intend to visit it again.