The tickets suggestion was a good one - so I had a look around and decided to get a child's membership to the Museum. It includes the Sciencecentre. There are lots of hands-on activities and she can go along with both Mum and anyone else (she has a regular respite carer for a morning each weekend). I'm pretty sure they get to go in for nothing as carers, so it'll work out to be a cost effective day-out as well.

I'm going to keep some of the other ideas for next year's birthday, Christmas and so on.