I went there a long time ago (last year) and wasn't really impressed if i'm honest? Some of the toys were broken (dangerous) and there was a big step from one section of the room to the other - not good with a crawling/toddling baby. Also thought the price was a bit steep for what it was!
Have you tried the local surestart centres? They're all excellent and run so many varied stay and play sessions etc. Only cost £1 or £1.50. My kids adore the one at Marlborough school, and the north Isleworth one on west thames college site is great too (staff lovely too) Redlees one oclock club excellent too (1pm - 4pm) only £1.80 and it has massive outdoor area with sand pit and play houses, indoor craft, ball pool and role play area, and sensory room. Hope that helps!! x
There is a small kids zone at Snakes & Ladders at Syon Park. It's loud but kids love it and there is something for all. You are not supposed to take food but I take a large bag and hide food and drink in it. Though I see other people being more open about it.
There is a lovely little soft play section (and it's free!!) at the Osterley garden centre. All three of mine like it there, and there's tables outside if you want to meet other mums and have coffee/cake. Car park too so accessible x