I have done some on Exmoor, I was looking for more evening type shorter trails, I have heard there are some north of Braunton in a woods somewhere but I am buggered if I can find them!!
I did make inquiries in South Fork too but they all shrugged there shoulders, either they don't want me on them or they don't exist
Did it back in 2006, quality time was had by all, can sometimes be frustrating if you are of the faster breed on the downs but over all a superb day riding some quality trails.
enjoy
this is me at the end, still looking quite fresh to my amazement