You should be easily getting cover for less than £1k with those details with Admiral. Are you in a bad postcode area? Any other details that could be pushing it up? I got my old 350z when I was in my low 20's and cover for the 1st year cost £800 with business milage too.
If you can try it with family members as named drivers, especially female ones with good insurance records (mum, gf, sister). Dont be a named driver on your Dad's insurance, thats not legal AFAIK, but having them as named drivers on your insurance is