You definitely are within your rights to give the car back, I had heard other people complain about this, apparently it’s a safety feature, the seat Tarraco is the same.
So it’s a known issue and from what I’ve heard there is no dealer fix, I’d get onto motability.
My Tiguan has the full functionality and I’d be lost without it.
No idea why vag made them like this from the factory? But you’re dealer would have known I’m sure.