That sucks mate
When i was doing mine i changed things like, where the car was parked as for some reason having a car on the street compared to in the drive brings down the costs as people stealing wont know what house it belongs to to get to the keys, sounds stupid but worked on mine got it down another £100. Erm not sure what else could do mate? Guessing you have tried all the obvious insurers? admiral etc?
p.s. im sure there would be a few people interested in your car

(which isnt an option obviously

)