Chris

You need to establish whether there is already a wayleave in place for utility companies to do this work. Though it sounds to me as if neither VM nor your neighbour have troubled themselves to find that out. It sounds like your neighbour has simply told the installer that it will be fine, presumably on the basis that they walk on the cobbles without any issue so burying cables under them should be fine too.

But your situation is too urgent for the internet to solve unfortunately. You need to phone the planning office at your local council and make sure you lead on the phrase ‘listed building’ - if you make it about access and consent they will tell you it’s not their problem and to go hire a lawyer.