Adrian Flux is who I'm with and was the best price I got for my supercharged Zed. Since I've now sold that & am driving a Civic Type R when it comes to my renewal time I'll be using GoCompare, Money Supermarket etc etc to try and find the lowest quote possibly.
I suggest you do the same especially if your car isn't modified much if at all.
Also you can always ring Adrian Flux up after you've got your comparison website prices and see if they'll match it or even better it.