I understand that it is only the deeds relating to current ownership (and perhaps the transfer from the previous owner to the current owner) of a particular property that have legal significance.

For those with an interest in the history of houses this is a mixed blessing. Banks, solicitors and others who had been responsible for the safe-keeping of these documents (they include mortgage documents, leases, conveyances, indentures and so on), are now able to dispose of them by whatever means they choose. Some are offered to the owner of the property to which they refer. Some are offered to local record offices, thus making them available for research. Some are offered to dealers, who then sell them... and some are destroyed.

I have to confess that whenever the opportunity presents itself, I buy any such ducuments that relate to Forest Hill or Sydenham (these will, eventually, find their way to local studies).