Thanks Dean. Yes, I'm aware it's private property. The "collectors" I saw yesterday looked like they we're going to take the money straight to the shebeen, hence my asking to sign the book - I suspect it was the case as asking made them take off quite quickly.
Just a note, for when you discuss these issues with the owners again - the past 3-4 times we we're told (by folks at the "pay-point" by the house) to drive down to the crag, they'll come collect later. I suspect they count on the visitor impatience, and at the crag no-one is too fussed to see / sign a book, creating an easy way of pocketing the money for themselves. The kids never do this (at least not in my experience), it's always some of the older guys. The kids are quite strict, and gave us quite a chuckle in the past.

Thanks for your effort in trying to maintain and manage the access. I, and I'm sure many others appreciate it a lot.