My DB/SIL said Stonehenge was surprisingly small and is roped off.
Bath, on the other hand, is a town I love. Went there in the rain; didn't dampen the fun. If you get a chance, tea at the
Jane Austen Tea Room is superb - we are still talking about it 2 years later. I don't like restaurant cake - too sweet, density/mositure ratios are usually wrong. But they know exactly how to make a wide variety. We drove in to the outer parking area and then rode the bus into town (I suppose you are doing a tour) then walked around town. If emma'smom is a shopper, just sit back and relax - it's chock full of stores.
I've been to the British Museum in 1987 and 2008. Lots of great antiquities that the British plundered during their Empire Days, including Greek temples and the Rosetta Stone.
My nieces were 17, 15, and 12.5 when we were in England - but we had to go to
Legoland for them. It's just right for your kids' ages. It's located in Windsor (we also went to the area around the castle - that's pretty neat too).
Cheerio!