It is possible to turn a manual tailgate into an electric one after you get the car. My Skoda dealer offered to fit an electric boot for the Enyaq for £1500 instead of getting the Plus Pack (which is about £4000). There are kits you can buy so you can DIY, which is a cheaper option – check them out on Google.
I don’t know if we are allowed to do this to motability cars but I would just do it anyway if you need it. After all, you are adding value to the car!