Since it's a bug and there are no OTA updates (which were promised by MG but never delivered) and there is no way for customer updates it seems reprehensible that they can make a charge to do this. Even my £20 radio gets free firmware updates.
Just to clear up a misunderstanding here.
Yes it's not looking good for MG, them touting the OTA update feature and then never doing a single OTA update.
But...They never actually said they would be able to do OTA on the whole car, only the infotainment and since the update to be able to use Tesla chargers is probably going to be in the OnBoardCharger (OBC) MG actually never promised to do OTA for stuff like the tesla charger update.
To be honest, the reason is probably, that updating these cars is quite complicated and if done you risk bricking a costumers car in the driveway, which does not look good on your reputation.
Tesla and a few others have mastered it, but MG is probably not investing nearly as much money into making this work, and as a result they have poor software update capabilities.
OR...They dont do it, because they know it's a revenue stream. Car manufacturers have been struggeling to adapt, traditionally a part of the business was maintenance and repairs of their cars after they sold them, they knew there would be oil changes, tune ups, exhausts and timing chains needing to be changed and whatnot.
With electric cars the maintenance is a LOT less, so the brand garages that once earned some of their money on selling a car and then servicing it, now find that they have a hard time keeping the maintenance and service income.
That is probably also why for example MG does a brake fluid change every 2 years....Simply because they have to find something to do, when there is no oil, sparkplugs, timing belts and chains and exhausts to change.