Following this one up in case anyone comes back to it.. we used Woodyhyde in the end. 3 fields, one huge, loads of space, not specified pitches (another field with electric hook-ups if required).
New shower block in the process of being built, existing one will then become loos – it is currently ‘past it’s best’! (only 3 mens showers which led to queues).
Found the ‘ace rocky downhill’ referred to by RichPenny above – drops right into the campsite!! And directly opposite is another BW that leads up to the Corfe to Studland ridge so a perfect base to explore the trails (we did a 20 mile off-road loop as a family one day).
..rode into Corfe for fresh bread and beer from the new local shop there each day too. Nice bottled beer / cider selection from local breweries 🙂