I get down that way occasionally to ride out with my son.....it is his local spot. We ride in Haldon Forest. I can give you links to my you tube channel if you have not ridden there before. I did a video of both the blue and red trails.
Yea, we're from Exeter and and ride up to Haldon quite often, you should also check out Café side, there are some good off piste routes with some technical stuff and some decent jumps.