ant 89,
Thanks for posting the update on the remedial work being carried out by United Utilities, clearly the message has got through, that you cannot just leave these underground drainage levels alone without the probability of some surface damage.
The note you posted by the company to local caving clubs is interesting, since it implies that they are aware that exploration is taking place.
I wonder if they are in fact just letting things, happen, in this respect, since GCC could legitimately claim that they have being doing this for years and nobody has objected to them officially?