You'll know what a minefield it is, then. One thing I have learnt is that fully comprehensive is sometimes cheaper than third party, fire and theft.
Just last week one of my daughters thanked me for saving her £100 on her car insurance.
Apparently, because there are occasions when I drive her car, she decided to put me on her insurance and because of my years of experience, accident free record, and clean licence, her insurance was reduced as opposed to being increased as she expected.
As has been suggested, going on line to compare is your best bet.
I forget which site it is but there also is one that you can go on to get revues of insurance companies. i.e. service, value for money etc. The cheapest is not always the best.