I did not wait for BP – I contacted the DNO and had them upgrade the fuse from 60a to 100a after having our sparky upgrade the tails (the DNO will not upgrade the fuse unless the tails are 25mm & they do not do the tails, that is after the meter, so your responsibility).
The upgrade was free, as they did it as part of my unlooping, but some DNO’s charge for it.
We never got any further than BP saying they were working on a quote – that was after 5 months. I gave up in the end and installed a unit at my own cost, life’s too short to deal with incompetent companies. Motability were not interested in the situation, although they did seem to change that a bit after we had ours done and are now using Ohme which has to be better than the BP “experience”.
In life, it's not who you know that's important, it's how your wife found out.