In just 4 weeks it’ll be the London Mini Maker Faire at Elephant and Castle. You can still get tickets and take a look at some of the cool stuff that is likely to be there. Also I know that they were looking for volunteers as well, so if that’s something you’d like to do it might be worth see if they still need people.
I was at last year’s event, which was the first year that it ran and it was excellent. Anyway, full details plus tickets etc here.