I meant that the BCA fee was very beneficial in terms of value for money compared to getting sued to death if there was ever any incident....
Absolutely
There is some benefit for the landowner from the insurance in an indirect way.
A landowner who grants permission for underground access could be perceived as being potentially liable under the Occupiers Liability Act 1957 which covers permitted access. (The 1984 Act deals with trespassers). There is however an exemption where the permitted person is fully aware of the risks involved, understands them, and is prepared to accept them.
The fact of that person having public liability insurance covering underground exploration would be perceived in law as making that person a 'potholer', and a potholer would be perceived as knowing more about potholing than the landowner whose land contains the cave or mine.
My avatar is a poor likeness.