We only have two days in London. Tower of London scheduled for afternoon we arrive day 1. Churchill War room Scheduled 2nd day 10:00 am. We want to do Westminister Abbey. So my question is what time should I schedule Westminister Abbey ticket that same day? Is the audio with the ticket entry sufficient? All the tours take so much time and our time is very limited there. We would love to hop over to Portabello Road Market, Drop in Harrod's, stop at a bakery for tea and scones, hopefully take a boat ride at night and just take it all in!
Schedule 90 minutes for the Churchill War rooms. Plan on having lunch nearby afterwards- possibly at the Blue Boar Pub. Schedule in Westminster Abbey for 1:30pm or thereabouts. With any slack time you can take a look at Number 10 Downing Street and the outside of the Houses of Parliament.
I would advise you to take a walk in a Royal Park, which are one of the best things about London. It sounds like you will be near St James Park which is one of my favorites. Stroll around, sit on a park bench and just enjoy some nature.
There's a Pret basically next door to the Blue Boar, so you could also consider getting sandwiches there and eating them in St James's Park, which is about a 3-minute walk.
I recommend taking the verger tour at Westminster Abbey, if you have time (about 90 minutes). You can purchase tickets for that once you're there. It's an extra 10 pounds per person, but they move you quickly to the major points of interest, including a few areas you can't access on your own. The place is huge, and you could easily spend hours looking at all the memorials and tombs.
I spent over half a day in the Churchill War Rooms; for me 90 minutes would have been seriously inadequate. The war rooms themselves don't take terribly long; it's the Churchill Museum part of the sight that is time-consuming. Folks interested in that will not be happy with only 90 minutes. It's my contention that the sight is overpriced if you only want to see the war rooms.