I don’t know particularly in regards to Motability chargers, but i can say that our installation (we went private) sorted everything out, including a new fuse box.
@DumfriesDik should know, i think he had something done? If i recall correctly, you have to pay the extra work done and can claim it back then, but i might’ve gotten that wrong. He is in the very process right now though, so he should know.
Prior: SEAT Ateca Xcellence Lux 1.5 TSI DSG MY19, VW Golf GTE PHEV DSG MY23
Current: Hyundai Ioniq 6 Ultimate
Next: we'll see what's available in 2028.