When I had my double-glazing installed, the fitters cut through the BT telephone line (which formerly went through a hole drilled in the old wooden window frame).
I have cable telephone, so it doesn't affect me on a day-to-day basis.
Unlikely. If the line wasn't active then it is unlikely to be a problem unless you wish to return to BT, whereupon they might justifiably charge you to fix it.
Unlikely. If the line wasn't active then it is unlikely to be a problem unless you wish to return to BT, whereupon they might justifiably charge you to fix it.
Or you claim "the previous tenants must have done it" and it will probably be free
