Go for it Witzend.
Our daughter and three grandchildren have just spent three weeks with us. They were visiting from New Zealand. Mr M and I took the three children out all over the place without their mother. We went for a day in the New Forest, a day at Legoland, a day at the local country park, and we took their cousin there as well, so had four children. We went to Park Run, and to various local parks.
My daughter and I took them to London for three days where we visited The Tower of London, went on the London Eye, did the London bus tour and saw many of the sights, went to Hamleys, used the underground whilst there and used the overland train to get there. We also went to the Natural History Museum and had the Dinosaur afternoon tea at the hotel opposite. The children were absolutely fine. What I’m saying is it’s perfectly possible to take children out and about and have a wonderful time with them.
The theatre and John Lewis visit will be lovely.