I am afraid you really do have to shop around.
Your postcode and details will be different to everyone else's and what's good for one person's set of details does not mean the company is competitive in another postcode or scenario.
The easiest way to get a ball park is using comparison sites, although don't forget that some companies (often with "direct" in the name) do not use comparison sites.
Personally I have found Carole Nash to be good for me and they also include European breakdown cover so you don't need to buy AA/RAC.
I also know they have a good reputation for service, so don't forget about that. Cheapest is not always best.
Also consider using a cashback site like quidco or topcashback, they take a while to pay out but if you're buying the insurance anyway then it's an extra bonus.
