Very difficult this the insurance game varies alot. No two insurance company will be the same for a person. People swear by companies like Bell, Admiral, Elephant etc.
Me personally i have always found More Than, Tesco or Swinton to be good.
Each year on renewal the company im with always turns out to be more expensive, I then change over to another company and they are considerably cheaper...Come to renewal again it happens all over again.
I usually always start with comparison websites, Get an idea of whats the lowest i will be paying and then start going direct. Maybe give one of the sponsors a try they may be cheaper if you give them your lowest quote.