I don't remember the big Kensington museums being like that when I was a kid. There was a kids' section or two, but the rest was clearly for adults (and has stuck in my memory just as much, if not more than, the kids' sections).
Seeing the real Apollo 10 (I don't remember which module) sticks very clearly in my memory.
I also rode on a "heritage" train recently, and what struck me the most was that the interior decor of the passenger cars looked as though it had been designed for and by grown-ups.
> Seeing the real Apollo 10 (I don't remember which module) sticks very clearly in my memory.
The only part that made it back to Earth was the Command Module, so if you saw something from the actual Apollo 10 mission, it was the CM.
Yep, makes sense, and looks like they still have it:
https://collection.sciencemuseumgroup.org.uk/objects/co40509...
I have taken my kids to them at various ages (from five upwards). I think lots for both adults and children.
The National Gallery used to do great guided tours for kids, explaining paintings in a fun way.
The blue whale skeleton hanging from the ceiling of the Museum of Natural History left an indelible impression in my mind when I was six.
I hope it's still there.