It depends on how much hassle you want. If you want a quick sale, we'd recommend sticking on eBay (perhaps as an auction) with an honest description and some detailed pictures. It'll achieve a fair price and hopefully won't be a long process. Alternatively, if you fix the roof and tidy up the paintwork, you could try advertising it on sites like Car and Classic for strong money. Also, look at some of the new classic car auction sites like Collecting Cars and The Market – cars like yours seem to make fairly high values on those. Or you could try a physical auction like Anglia Car Auctions.