Depending on your needs, would an ethernet cable not cover it? to move a master socket if you have ADSL or FTTC is £130, to move an ONT if you have FTTP is around £98, it's the fee Openreach charge all providers for relocating equipment.
The move won't take too long, so you won't be supplied with any backup device, unless you have Halo 3+ as that would kick in automatically.
Thank you Richie. I need to relocate my static home for builder access so the ethernet option wouldn't work. Thank you for the numbers. Much appreciated.