Hi Brydo,
Sorry to hear this.
As you know, Bionic Rusty has been having similar problems, and I recall somebody else over on the XC40 forum having problems earlier last year.
Ours is an Inscription (non Pro) and the seats are marvellous.
From the little I know, it does seem to be the Pro models with the extendable bases which account for the few affected.
Hope Motability are sympathetic – this may be a way to change the car, as I recall you’re also disappointed with the MPG!