Hey Danny,
I use
www.moneysupermarket.com for comparisons, but then I also ring Direct Line who tend to still be the cheapest for me and use them, they've been cheapest for me on the Z3, Focus and Mondeo.
If you put someone on your policy as a named driver, for example - your mum, then this can make a big difference. Its completely legal too.
How is your home postcode rated? Give them someone else address if insurance is cheaper for a different area.