if your looking at mk4 and have about £1400-£1500 speare then just get yourself a 1.8T, did a qoute for my cousin and came up at about £1000 and hes 20, no no claims discount, no claims, 2 yrs driving experience.
contrary to popular belief the bigger the car the cheaper. i worked for Directline and Churchill, i found that if you buy those Corsas

Saxos

KA

Fiestas

...anything that a young driver would go for then you'll be paying through the roof, Mk4 Golf 1.6 for a 18 yr old was qouted £2800, same kid i qouted for an Audi A5 3.0 y Plate, out of curiosity came up with a qoute of £1200, the reason being is that insurance companies for under 21's have an automated system that is based on your age and driving experience in yrs first before taking into account the area you live in, mileage, occupation etc etc
best way to be sure though if your not convinced is have autotrader up and compare the market plus any insurance companies that aren't on compare websites and also give skyinsurance a go, their link is on the insurance section, i was qouted quite good by them
