I agree, but getting insurers to rule on something is like pulling teeth.
I have tried it many times.
They just say "you have to comply with the regs, etc".
The most charitable explanation for this behaviour (incidentally mirrored by my house insurer) is that they are reluctant to spend money on lawyers, in getting the answers.
Half the job, IMHO, IANAL, is that making a full disclosure of the intended operation to the insurer gives you some protection (from them walking off a claim). I bet there is a ton of case law on this though... it must come up all the time.