Thanks CNCC for the detailed explanation
I'm aware that some places can be accessed without going via a booking system, even (so I hear...) many common padlocks can sometimes open/close without leaving a trace and nobody being the wiser. However I'm aware of the access situation having been negotiated with landowners and so intend to do everything as legitimately, courteously and respectfully as possible to maintain everyone's current access.
Assuming of course that weather is clement and my trip goes ahead... I'll be sure to feedback estimated rope lengths, deviations etc if anything significant, following https://cncc.org.uk/caving/report/topo-error.php
I understand that you cannot endorse the use of any anchors that haven't been CNCC installed/tested but if it was the case that deviations were actually necessary to land on the ledge (I have yet to discover the facts here) and they were omitted from the topo then it would be misleading. So I guess there's a balancing act there. I still think you should include some unapproved anchors/deviation with a skull and crossbones symbol and "do not use" in the key to cover yourselves if a topo was misleading otherwise. As mentioned no idea yet if that applies here
All the topos online and all the advice generously given here is greatly appreciated!