my advice is to sack them off, on my previous car i added an exhaust mod and they wanted an extra 200 quid. also i canx my policy early because the buggers wanted an extra 1500 to change up to the Zed from my ST, i was 6 months in, but worked out cheaper to get rid of them and start again.
have at look at:
chris Knott
sky insurance
adrian flux
and livingston warnam
all to be found on here, that offer very good discounts for forum users