a few thoughts -
if there's anything at all non standard about you or the car, can be better tracking down one of the remaining traditional brokers - the online comparison things are about the high volume market.
make sure the annual mileage you declare matches what you do - if you're over-estimating the mileage, or they are assuming an average and you don't do much mileage, you may pay more.
can be worth upping the voluntary excess (the amount you'd pay if there is a claim) so that you're effectively self-insuring for anything less than X amount
conventional wisdom is it's cheaper to go 'fire, theft + third party' but it can actually be cheaper to go comprehensive - apparently people who opt for FTTP are seen as higher risk.