However, just after I printed the guide the Cycle Centre was demolished and the BMX track re-located. Fortunately the new Cycle Centre is superb and well worth a visit. You can buy anything from a puncture repair kit to a new bike.
Apparently the BMX bikers were riding around on a route that had been laid out on top of an archaeological site. (This explains all the rough ground, hills and deep pits). The bikers are still there but all the signs have gone.
Since the book was published a number of new mountain bike trails have been established in the woods. They all start at the visitor centre and are clearly signed.