"Hi Chris,
We just wanted to officially write to you to thank you so much for making our daughter's birthday a memorable day. The children and adults all enjoyed your show and it has been the topic of conversation ever since and all over "facebook" today.
We only wish we had booked you for longer and we had had your bit of a disco with what we can only guess would have been equally as entertaining.
Thanks once again Chris and please dont change what you do, its brilliant."