I am with admiral always found them the cheapest especially on multicar, i am now 24 and just insured for my 3rd year with them. Started off with a mazda 6, then a nissan terrano, ford mondeo now a discovery. When swapping the cars mid policy they always seemed quite reasonable as well not shafting me for changing.
The fella from adrian flux quoted me and was a little bit cheaper this year, only reason i didnt change though was because only about £15.00 difference in the end and couldnt be bothered with the aggro of swapping.