Personally, I think if a guest cancels, then you should be entitled to your refund AND your entrance fee as well.
Not being funny, but I would imagine there are a lot of people like me who have planned their trip SPECIFICALLY to meet certain guests, then they cancel, so why should we have to pay out over £50 for an entrance fee for guests that are no longer going to be there?
I think that's totally wrong and will be taking this up with showmasters personally.