well after my bump the other week and car been classed as a cat b then a cat c so i can retain the car ive now been given a offer of £251 pre-accident value so i phoned and said i not accepting it paid £900 for the car less than a year ago

Hard to value, but more than that! Insurance companies always offer low. Argue it by providing the insurance company examples of others for sale (if you can find any) and disputing about it's condition, rarity etc etc. I wouldn't even tell them how much you paid for it. It might take some time but you'll eventually get them up to a better price.
I'm sure a few people on here wouldn't mind sticking up a dummy ad on Pistonheads or something to aid your case.

had the same experience mate http://forum.405mi16.com/index.php?showtopic=238 was lucky that 3 overpriced mi16s were in autotrader at the time , i photocopied them and sent them to the insurance...