It's a new car, unknown to many servicing garages, and cost me quite a few thou so I'm happy to get it serviced by MG. I am expecting to get a service plan for the convenience but may not.
The thing about services is if you look at the schedule for most (ICE) cars a lot of the service plan is checking the lights are adjusted, the seatbelt isn't frayed, the tyres are at the right pressure and the washer bottle is full. Occasionally you get something useful like an oil change, or cambelt but not too frequently. So given that an EV has none of the ICE complications there oughtn't be too much to it, whoever does it.
But a second buyer might be interested to see a Full Manufacturer Service History so to could add much more to the value than it costs.