i'm sure they pull these figures from a hat.
this year my renewal went up from 740 to 780. Even though i now have two full years NCB. They claimed that this figure was picked out by their computer and they couldnt alter it.
so i phoned up tesco, and they quoted me £570. Which my current insurance company has just matched...ookkkaaay then. £210 saved.
why not just offer a half decent renewal in the first place?