A video from the pump track with some messing about on a BMX and a bit of dirt jumping too.
Oh and me embarrassing myself at the end.

50MB Download, 640x480, 4mins

I was thinking I might put up a Youtube version tomorrow.
^{(Not enough time now - going away for a week)}

It's public in that its just built on 'waste ground' but it's unofficial, so we prefer to show visitors in person, rather than broadcasting directions to it on the net.

Can i ask what area of the country its in?

North Derbyshire
Build your own one, it's not that hard.