W-Dave - I've not seen an entry form for this year yet but £12.50 sounds about right, even though the entry for last years Dash was only £10 (from memory). Even with a 25% increase, it is still pretty good value as it includes the cost of your full Santa outfit and after last years race, we got what is probably the best stocked goody bag I've ever had after a race - and that includes the FLM!!
The bit about each participant raising £20 in sponsorship was there last year too. Like most things, it's the serious bit of a fun event, where people can have a good laugh from doing the Dash but also do a bit of good in the process. Of course, it's up to each entrant as to how they cover the £20, if you choose to stump for it yourself then yes, it does effectively cost you £32.50 to enter! However, it doesn't take much effort to raise £20 by doing a very simple sponsored event at a workplace or club or even amongst a group of mates in the pub one night!
Last year, I decided to adapt the football card theme that is commonly used as a fundraiser, only instead of it being a grid containing the different names of football teams, I substituted this for a range of finishing times that I might do in the race. I split the most likely 5 minute period that I would expect to run approx 5k into 30 boxes of 10 secs per box and people guess at your predicted finish time. If you charge £1 per box, you raise £30 which is split £10 to the winner and £20 to the charity. Problem solved and it doesn't cost you any extra!!