Wow Bexy, firstly thank you very much for your donation. Very kind of you.
I did London to Brighton last September and took on the beacon and just about won. I loved that and raised £1,000 for childhood first. It felt amazing to do it and to raise so much for charity. May look into the one you are doing as it sounds fun!
Next spring I want to do the 3 cities London, Netherlands down into Belgium. Not sure who to do that for but might do something for a local charity.