The Title Register is created or updated from information contained within the Transfer Deed. The Transfer is one of many Deeds created in a typical conveyancing transaction. Previous to land registration the conveyancing deeds authenticated ownership of a property, but now the Title Register and Title Plan are used instead. Nevertheless, conveyancing deeds still have their uses, and they contain substantial practical information. They sometimes have Deed Plans attached to them that provide even more worthwhile data.
The Land Registry have made many of these available for purchase by scanning and digitally storing them. The Deeds available for purchase are those which contain a note in the register that they have been copied. They are useful in boundary disputes, rights of way matters, and when requiring more detail or antecedent history of Covenants and easements.
Including an up to date copy of the Title Register and Title Plan with your purchase would furnish you with a complete and up to date set of your property ownership documents.