Old junction box -> new master socket

[#1]

I need to get the ancient junction box attached to the inside of the front door frame replaced with a modern master socket  elsewhere in the house (because I'm replacing the door!). So presumably they cut the wire going towards the door and train it in another direction.
If that gets done, and the phone line master socket comes in through my front room wall to a new single master socket , I can completely abandon the Heath Robinson phone wiring inside and round the house with a combination of cordless phones, wifi and Powerline, as the router and main phone base unit can be near it.
Am I right in thinking the way to get it done it is by Openreach via Plusnet?

[#2]

That's logical if PN is your phone provider, but price will be steep.
Unofficially you could get a sparkie to undertake or yourself if competent
Officially you can't touch wiring up to the 1st junction box, but many have including me.
Had Openreach Engineer in a few weeks ago & he didn't say a thing.
E Bay have "Openreach" master sockets, presumably sold by Openreach Engineers or their contractors.