Hi @Emily. What a shame you are trying to join the scheme now, the worst possible time.
As @Laura says, reach out to Motability and see what they suggest.
Many people are having long lead times for delivery and your husbands idea seems like a good one. You could place an order and whilst waiting run the second hand car – sell it when the Motability car arrives?
All the best.
Skoda Enyaq Race Blue