You need to target a young driver specialist such as
http://www.youngmarmalade.co.uk.
I'm an insurance salesman (not for young marmalade), from my experience It is best not to buy a car that is popular with young drivers i.e. Peugeot 206 or ford kia as these will have been involved in lots of accidents, which will increase their insurance rating. Plus, a lot of insurers don't like japanese manufactured vehicles, so a nissan isn't a great buy.
You'll be surprised how cheap you insurance could be on a 2 litre late 1980's jaguar, because these are popular with middle age driver. You can buy a decent one for a grand.
For more info go to
http://www.squidoo.com/tips-4-car-insurance