Insurance companies are like bookies, they calculate the risk based on past claims and set the premium to suit. With something like a Corsa, being popular with youngsters, the chances of a claim from a Corsa driven by a young driver are pretty high. With something that is considered uncool, so not popular with the high risk drivers, the chances of a claim a much lower. A mates son (19 year old student) was trying to get insurance on a Fiesta and being quoted stupid money until he got a quote on my mates old Peugeot 405 diesel and the cost plummeted. The reasoning being that the odds of a 19 year old student in a Fiesta making a claim is around 100%, the odds of a 19 year old student driving a 405 diesel making a claim are considerably lower purely because 19 year old students don't drive 405 diesels so past history shows no claims.
So, think outside the box and go for the most uncool car you can find.