Special anniversary day out for grandparents

[Marmaladetea]

Hi
I would like to give my parents a special day out for their wedding anniversary, but am unsure what to do, other than an afternoon tea. (London or east/ south east). DM is a bit rickety on her feet and can't walk too far. They like everything esp arty stuff. Any suggestions v much appreciated.
Many thanks

Hever Castle - we went for one of their many jousting events and my DF really enjoyed watching that. There's a boating lake, a good exhibition of model houses, Japanese tea house, apparently the second best collection of Tudor portraits in the country and lovely gardens. The majority of the gardens are easy to get around, there are lots of benches to sit on and you needn't walk far to find a beautiful, peaceful spot. We liked the sensory garden. If you're going with kids, they'll enjoy the playground, mazes, archery and shield painting. There's also a military museum which takes about 30 minutes to stroll around and it quite interesting.

Thanks that's a great idea I'll look in to it