I reckon if they offered full refunds, then you'd get lots of people entering thinking well maybe I will do it , maybe I won't but it doesn't matter 'cos I'll get my money back. Not good from an organisers point of view.
As for £275 being a lot of money, well yes, but having seen the event at the weekend, I can see where a fair bit of that will have gone. Event HQ, marshalls, timing, road closure, security, marshalls, and of course some profit for the organisers.