If you are looking for something fun to do as part of your trip to London with children, or even on your own check out https://www.morphsadventurelondon.com/
Morph is a childrens tv character, I had not heard of him my the staff in my hotel watched when they were young. To raise awarness of accesibility artists have greated 56 large Morph scupltures around London. They are located around the city and each is decorated with a different outfit and message. They will be auctioned off in late Aug to raise money for charity. I had fun looking for and finding all 56 of them. It became sort of a mission to find them all once I hit about 45. Many are grouped together such as near St. Pauls and near the Tate and Borough market. I saw a few others searching for them as well. There is an app which I did not download it was a paid app. I just downloaded the map.
Some are decorated to reflect the areas they are found in such as near the Globe, tower of London and Tate.
Just a fun free activity that many not be on the radar on many people