Its now Free to ride, you just need to sign in and out. I helped start it back when it was MTBfreeride years back it out grew us with in a few years and now the UKBP guys are running it properly its looking very good but I havent been back riding in years (stopped riding for a couple of years) Planning to get down riding again some time soon.
The push up is very nasty and its very steep too both going down and on the push, The top is a hoot too ride but best thing to do it catch it on a uplift day and then you can take advatage of the whole site there is also Puddletown Forest about 30mins away which has some great riding loads of singletrack and plenty of variety.
If you can try and make a weekend of both places, both worth a visit IMO.
Dave.