My dd aged 9 is over for a fortnight this summer and we have always had a tradition of checking out a new playground together.
She is quite fearless, so we are after something that can offer both a challenge to an older child and where a juvenile father who should know better will not stand out like a sore thumb (bless her, she is still not quite at an age where these things embarrass her).
We live in Bromley, but will gladly travel anywhere in London.