They came to DD's school to do an activity (free for the school I assume). Leaflets handed out. We ignored.
Then they had 'refer a friend day', we went along at another mum's recommendation. DD is 6 and they seemed to do some running around and singing, fun enough but not exactly ground-breaking. The problem was the fees, which were astronomical, I don't remember the exact figure unfortunately (and they don't put it on their website), but it was ~£180 for 10 1.5 hour sessions, and if you can't come one week well that's tough.
Since then we've had mailshots, '£40 off your first term' and all this other marketing bumpf.
There are lots of other activities locally, DD does ballet, with a teacher with lots of experience and smaller classes than Perform (I think they have up to 20?), and the Perform website doesn't offer any credentials at all for their franchisees: www.perform.org.uk/about-us.html
They seem to be doing pretty well, albeit that they are confined entirely to London and commuter towns, but AIBU to think that paying so much money for a large group activity for 4-8 year olds isn't worth it all?