insurance on a cab is going to be more because of the high theft risk (soft roof and all that), best thing would be to contact someone like HIC or brentacre that specialise in performance cars and young drivers
also if the cabs going to be a project car then it might be worth spreading the work out until you have a full years ncb behind you with the mark 2. classic insurance with a limited mileage would also be much cheaper. but this doesnt gain u any no claims bonus
brentacre,
HIC,
tesco,
elephant
are all good, but try
www.confused.com for loads of insurance quotes at once