I'll be going with the firstborn, a fairly nerdy (math/science flavour) introvert with a voracious appetite for knowledge and a dislike of crowds. So far we're thinking something along the lines of the following:

British Museum
Kew Gardens
Science Museum
A Hidden London tour if possible

Add to that a lot of general walking around and at least three excellent meals a day.

Any recommandations for either?

2/2