Hi Adam, I had the same problem, had a company car for 30yrs so didn't have any no claims of
my own even though been driving 50yrs !!!
Mine was over a £1k for the first year, but mine is an SRT. this year dropped straight down to £364
with only 1year no claims !!! thats with Allianz.
My husband has a couple of customised cars that need specialist insurance and he uses Adrian Flux
Insurance, they insure Classic Cars as well and are very reasonable. you may have to suck it up for the first year but I promise it will be worth it