@kezo I recently had a 7kw charger fitted then received a letter from the local DNO informing me that, as I am on a looped supply, they are digging a dirty great trench from the road and down my drive to fit a 3 phase supply to my house. This is to ensure that I wont have any problems with my supply when the car is charging and it is being done free of charge. Apparently there is a grant for doing the work, I didn’t have to do a thing, it all just happened, I do wish I had known beforehand though, as I could have had a higher rated charger, it would have also made me feel less aggrieved about them wrecking my drive.
A looped supply is where you share the incoming with a neighbour. Either you or your neighbour would have 2 cables coming into the main fuse (carrier) (load sharing) Your main fuse would be either 60A or 80A with 16mm incoming cables, even though it may have said 100A on the carrier.
The fact you have had it done for free is because your system needed to be upgraded before you could have a charger fitted and as a bonus you had a upgrade to a 3phase supply, which isn’t always the case. Your electricity supplier would also have had to fit a 3phase meter.
On a plus point your are now future proofed for free and it would simply be a wall box change should you choose to install a 11Kw or more charger.