That sucks Craig ~ feel for you as that's a lot of money for anyone to have to pay.
Try ringing/emailing & sending PM's to a few of the Insurance companies on here as JC mentioned. They can be found here; http://www.350z-uk.com/forum/42-insurance/
Failing any of them, which I doubt, your next best bet is to get on a comparison website as that is where I found my cheapest quote. Be careful when checking what's included etc as the cheapest quote isn't always the best. Good luck.