I'm with Sainsbury's Energy Fixed 2Yr till Oct23, apparently they are an extension of E-on Next.
I rang Sainsbury's and they said they had NO EV tariffs, suggested I should try E-on Next, but haven't.
The Granny charger was taking too long to fully charge up the MG5.
So bought a 7kWh (32A) plugin charger off Ali-Express, quite pleased at the price of £153 inc P&P, rather peed off at the £55 Customs charge though.
I already had 16A and 32A Round sockets for my Welders and other equipment, but they were a bit inaccessible for the charger.
So bought a combined Switch and 32A Socket, to mount closer to the roller garage door, when leaving it plugged in(which takes 6Hrs), I close the door down to just touching the cable, works very well, 32A Switch/Socket was £30 off fleebay, already had a coil of 4mm² cable so job done.
Put on charge today at 18:00 (18%), unplugged at 21:00 (100%) stating 316 Miles range, well pleased.