Actually, thinking about this, there is a much simpler approach that would be zero risk. As you still have the Tiguan, why not go to a Skoda dealer and ask what the part ex would be for the Tiguan against a new Enyaq and also ask what the price would be as a cash buyer with no part ex. Then you can do the maths and decide which option is best. I will be absolutely staggered if it pays to buy it from Motability and then use it as a trade in, given the over inflated prices that they always ask for their cars, but this would answer the question once and for all (well, as far as Skoda is concerned).