I personally don't think you'll make more than £500 for it broken, how much demand is there for GTV parts? Personally I would be all for selling the thing off complete to get rid of the damn thing, I reckon you could even get your £800 on ebay. Although Autotrader in my opinion is by far the best place to sell a car, never failed me everytime I've sold first time on autotrader. Upfront costs might seem relatively high but it works and well worth the money.
Anyone remember the last breaking thread, all ended in tears.
Alfa Romeo GTV T-Spark