Spotted...

I don't think you can use it unsupervised and it's only accessible when the gates are open anyway.

There are plenty of good bridleways south of London where you could let loose though. Andrey and I did this route a couple of weeks ago:

http://www.cross-crazy.com/index.php?option=com_content&view=article&id=865:favourite-rides-3-three-pimples-cross&catid=41:specials&Itemid=29

Hah- that looks like an off-road loop inside my (road) Sunday training loop!

I'll have a crack at it this Sunday if I get my tyres off Scott in time, cheers Andy.

Hang on, it's Lycra for road bikes and baggies for MTB- what do I wear to ride cross?