Its Openreach that own the lines.
Its unlikely they will remove it because it may be needed for another customer in future. If you are making alterations to the property, then they would charge you to relocate the wires.
It seems unlikely I can be held responsible for something on my property just in case I sell it in eventually
As this is just a BT Retail forum, you will have to take it up with Openreach, as they use their network to provide service to lots of providers, not just BT Retail.