Buying and selling land . . . without proof of title

Conveyancing! Thanks to a wonderful organisation called the Land Registry the process of deduction of title has generally been a lot easier of late. But there are still large parts of the country which are unregistered and even many small pieces of land which have been in the same corporate ownership for many decades. For these pieces of land the Land Registry does not hold much information (maybe details of some Land Charges).
No for these properties we must rely on the deeds. On that basis you would assume that those deeds would be treated as gold by the owners of such property for without the deeds there is no proof of title and without proof of title you are going to struggle to sell the land.
So I am now in the rather unhelpful position of acting where the deeds appear to have been lost with no copies available and the client wanting to sell a piece of land. When I come up with a solution to this problem I will let you know . . .