In reply to Alex Ekins:
There was a great site in Trewellard. Heading towards St Just turn right opisite the pub. 100 meters down the lane on the left is a gate into a field. The house looks a bit like the one behind the Bates Motel but it fine. Jacky, the lady that runs it is very friendly and helpful.
Good, basic facilities. Toilets, showers. And its handy for the pub. Good food.
Very handy for the North coast crags. Senen etc are about 20 minutes to 1/2 an hour drive.