If you needed that power as part of powering mobility equipment I’d get onto motability and say the car isn’t suitable and say there’s no power in the back.
You might have found you couldn’t charge a scooter off that 230v socket anyway a lot of chargers don’t play nice with cheap inverter power and knowing car manufacturers it’s probably as cheap and dirty power as they can get away with. You might get lucky but for some equipment you’d need a pure sine wave inverter not whatever that Vauxhall install, or dont