I'd put my vote on a Focus/Fiesta. You can get reasonably priced Mk6 Fiesta's, and they seem pretty reliable.
was actually more thinking of extra skills after passing the test rather than saving money , as the OP wont have much experience with motorway / dual carriageway driving , nor at night and/or bad weather. first time your on a motorway @70 and get overtaken by a foreign registered fully loaded lorry is a little unnerving
Id go focus over fiesta mainly from insurance cost. The fiesta is whats classed as a learner car so insurance is often higher. Plus the focus is easier to look after and more practical.
Then I'd recommend saving the money, and just having someone who has passed go along with you will be as beneficial. Also if he's going 70 it will be kind of hard to have a foreign lorry overtake you
I learnt the stupid way, went from a 75BHP corsa to a 200BHP Saab estate and the saab costs me less on insurance!
Similar effect with my RS compared to my ST170 when I had both! Never thought about Fiesta's the same way though. Ah well.
erm you haven't driven on the M25 recently have you... been passed by a lorry when I was the wrong side of 80 (think it was Romanian)