My son decided where the fuse box was did not really work, so doing a full rewire over time, he put the consumer unit where he wanted it with an isolator along side it, with tails from isolator to new outside box for the DNO stuff so meter can be read without going into the house, and a 10 mm² cable from the biggest breaker he could find to fit old box to new consumer unit while waiting for DNO to move head.
So as soon as moved all he had to do was remove 10 mm² and fit tails from isolator to new consumer unit, and if they did it before he had finished rewire he could use the 10 mm² to feed in other direction, main reason for move was to get rid of cables around outside of house, as building work would cover them.
It took 3 years for them to finally move cables, the location of box was where cables came out of the ground, so should have been an easy job, and he was given a quote which he paid in advance, however it turned out that without the way-leave, some one had wired next door through the cables around the side of his house, and in that 3 years next door had changed hands and new owners laid a new drive.
Sons building work was stalled due to lack of funds, so it did not cause him much of a problem, but the point is the DNO are slow, where I worked we wanted a new supply, for a new building, they came to see what was involved, and said before you build those over heads need moving at your cost, my boss said I know I paid for them to be moved 15 years ago, think you have had enough time.
It is not like the builders, if they are too slow they are sacked and you get some one else, you have to wait until the DNO gets around to doing the job.
When my son was working as a sole trader the DNO was his biggest head ache, they would arrive early and late, and he would get a frantic phone call "DNO have been and moved meter, you need to move supply now before freezer defrosts." i.e. drop everything and do my job. I would get roped in to help when that happened, a few hours early OK but talking about a week early. OK with a firm with 10 electricians you can juggle things a bit.
With mothers house when doing a kitchen and house wiring well past its best, kitchen supply was a steel wire armoured cable around outside of house, there is usually a way around the problem, but the Part P charges unless other building work involved means it is not really DIY work, yes in theory you can DIY, in practice not worth it, cost more to DIY than get a scheme member.
So get a firm to look at it, and see what they suggest.
