Its all down to the dealers I guess.
If youre 19/20 and turn up in a K-reg 1.2 then its unlikely youre going to get a test drive, but if you turned up in a higher value much more powerful car, the salesman might let you have a go.
I wanted a test drive on a new Punto Sporting, turned up on my motorbike and the answer was "no way sunshine", but a week later turned up in a 225bhp Volvo T-5 and no questions were asked, "come back in 30 mins..."
Clio1400