In reply to Alan James - UKC and UKH:
If it were really about access, and the need to ensure that climbers stick to the complicated Cheddar access agreement, then there could be no logical objection to Rockfax publishing with accurate access information.
If, on the other hand, it were about Cheddar Gorge & Caves wishing to monetise the natural landscape then it would be in their interest for Rockfax not to publish. Instead, they make sure that climbers all buy the Cheddar guidebook published by non other than Longleat Enterprises Ltd (the owner of Cheddar Gorge & Caves).
If the latter is the case, it's hard to imagine them actually threatening access, as to do so would totally torpedo the very revenue stream they were trying to protect. (Having done so, they'd no doubt come up with some kind of Cheddar permit system...)
Which leads to the conclusion that it's either a bluff, or it's yet another case of local climbers thinking they have some kind of additional rights to a place. Quite why the landowner would get on board with this is beyond me...