Never seen this before myself.....

[davesparks]

I'll just put this here:
https://www.ukpowernetworks.co.uk/internet/en/help-and-advice/documents/looped_services.pdf

I was just looking into the looped service issue I have in my own property - supply comes into my house and then looped to my neighbours. Problem is their cable runs up underside of my stair and under the floorboards of my house into their property. If I wanted to carry out major renovations like repositioning the stairs, I can see their cable needing disconnecting. What then! I envision major issues and irate neighbours.

That's easily solved, just leave the staircase where it is.