A Lamborghini Reventon is sensible? You also suggested earlier I get a 4.3 litre Lexus as my first motor...
It may be a bit of a fight but at least you can get something sorted. My sister bought a Punto from a car dealer 3 months back for a grand. The steering was buggered after 2 months but CAB contacted the dealer for her and let them know that wasn't acceptable. They fixed it for free.
You can say one anecdote proves nothing but the law does give you some backing.
I think people aren't factoring in the cost of insurance for a new driver, checking an insurance comparison site for a 1.2 Polo I'm getting quotes of £1,350 cheapest. There's not much point in me checking out anything over 1.4 is there?