We have never cancelled due to a test drive in fact we always are unlucky with test drives
our current vehicle would be hard pressed to find one to test. However we have benefited on 4 occasions including this current car when a Motability customer does cancel and this time it was because vehicle arrived but charger did not so guy cancelled and we got a car in 4 days instead of 18 months so I always tell dealer to let me know of any cancellations and if you are genuine they will. The downside is why I am still driving my 3 rd grey car when I keep ordering red ones.
I am the carer / driver for my wife who cannot drive due to disability