UPDATE: I've done it! Yesterday, March 10th, I did a 4 mile cross-country gallop over 23 fences and hedges, and followed it with a couple of hours hunting (a further 8 miles or so, and 11 more jumps!) ALL WITHOUT A SADDLE!
I did it to raise money for Help For Heroes and Yorkshire Air Ambulance - and I'm asking you to donate now! Simply choose which charity you'd like to donate to and go to that page. Alternatively, and indeed preferably, split your donation between them by going to both pages and donating on each one! The first link below is for the Air Ambulance, the second is for Heroes.
The combined total from both pages shows on the right here.
Have a read on the individual pages anyway, and I hope you feel compelled to donate! Every little bit is greatly appreciated.