Well on the weekend I attempted the London to Brighton bike ride, not the official route, but a much more INSANE and PAINFUL route, because I am a retard and used google maps (That and I dont know quite a few parts of the official route). I made it, but after about 50 odd km (just after turners hill) my GPS lost its 3d fix, and I was relying on its 2d map to navigate me allll the way to the beach, which I made, eventually. Total time was in the region of 4 hours, which isnt my best time, but in my defence it was bloody cold, wet in places, and bloody windy. That and I screwed up the route, and went up Caterham Hill, for NO REASON!
Anyway, heres a height map of the route (most of it, till turners hill, then it went a bit funny after that and then just stopped):
