Ok, here's mine after booking it in specifically for a BMS update due to a breakdown (high voltage isolatation, would not boot after full charge) when we were away from home. It looks like they updated the infotainment system and did nothing with the BMS! Car purchased Feb 2021. Am I being dim or is this a literal example of bad service from an MG dealer?
Although the MG 020 software update for the head unit should be welcomed, I very much doubt this caused your issue on holiday that’s for sure !.
What did they do to rectify THAT fault condition ?.
Head unit software update, simple to apply, hard to get wrong.
BMS update, different story.
Get it right and your clipping your heals all the way down the workshop, get it wrong and your in a whole different world of pain !.
Ask them what they did to resolve the original problem ( when on holiday ) and then WHY they did not carry out your request for a BMS update, after booking in the car directly for this work to be carried out ?.
Senior EV Tech on holiday maybe

.
Push it back for another day ?.