modified !!

hi there all, I have a 83 golf c which has been fully converted to a gti, the C's body shell was so good all parts were swopped. I had a mk2 8v gti and got insurance for about 290 quid but most company's would not touch my mk1 as it was modified so I went with adrian flux and it costs me 530 quid a year. Is there a way to get round this modified buisness as if it was a standard true gti my insurance could be nearly halved. cheers