Just to throw my hat into the ring on this one…
My partner and I placed an order for our 1st Motability vehicle for a hybrid Vauxhall Frontera middle of last year, even paid a £99 deposit which I was informed via the lovely people on this Forum that you don’t legally have to do, however the build/delivery kept getting pushed back and we needed the car for a family holiday in late August. We found an alternative vehicle (Skoda Kodiaq) and was able to cancel the Frontera order, and get the deposit back, with no muss or fuss. Until you put your pin in at collection it’s perfectly fine