There is a soft play center in Tunbridge wells that have just started doing evening sessions exclusivly for children and young adults with special needs.
We took the children there this evening and they had a really good time and it was a good opportunity for the parents to get together and have a chat.
They are open from 10 to 6 daily and the special needs session(s) start at 6:15 to 8:15, although I don't know how many times a week or month they hold these sessions at the moment. Their website is www.ourspaceplay.co.uk/ which has contact details but no mention of the sessions yet.