jack and jill went up the ......

Box Hill is on the Olympic cycling route. It has an annual race up it called the Ball Cruncher which is 6 circuits of the hill and is totally knackering. I think they're doing it 8 times in the olympics before going on!
we were on the hill to do some fieldwork with Year 7 - a classic day in all senses. we got soaked within 5 minutes of getting out the minibus but the best bit was a fellow teacher said that the car park at the top of the hill was shut and that we would have to park at the bottom.
2 of the 3 minibuses waited at the bottom of the hill for 20 minutes before I phoned him to ask where he was. he was stuck at the top of the hill having gone up there to see if the car park was, indeed, shut. he then couldn't rejoin us as the road down to us was closed!!
WHY????