I'm sorry I didn't see your post before I went away. I know some people do park up and sleep in vans but I don't know where. For future reference you could probably find somewhere up Station Hill. I've no idea about nearby touring campsites. I hope you found somewhere last weekend.
When we ran the music and song session in the Rose and Crown public bar many years ago we always had problems with the drummers. For some reason they always felt they had to stand in the door of the pub!