Ask the insurance company their reasoning behind it.
I had an Opel Manta a long time ago, I was probably 20, passed my tests 6 months before. Costing £1200 a year third party. Then a few months later I brought the 3rd Gen Firebird this was only £700 fully comp. I asked their reasoning behind the massive price drop. They said as its left hand drive then people wont try to take it for a joy ride, and with it being manual it makes that even more difficult.
About 6 years ago, I had to insure a second car for the first time, with all my no claims on the Trans-Am, and not able to share any onto a second car, I was starting with zero no claims bonus on a second car. The Ford Fiesta worth £500, cost me just over £500 to insure it each year, double the Trans-Am.