Insurance What a rip off

[lukiep160]

Just had my yearly renewal notice through today, £642.60p which i think is a rip off. i'm 23 been driveing 5 years with 5 year ncb, for my ZR 160.
Just done a search online and the ame company for the same policy want £526 so i phone them to see whats going on and low and behold all the operator says is thats the price and you have to pay £642. So now i've got the hump with them, i did a search with gocompare.com and the cheapest i find in £359 or £424 with protected no claims from more than.
Where do some of these companys get there figures from.