The purchase deed
Council of Mortgage Lenders
There is an online version of the CML Lenders' Handbook available at this site, and should be referred to in cases of doubt about the requirements of the lender in relation to the subject transaction.
You can download purchase deeds, e.g. Form TR1, direct from this website.
It might be useful to consult a detailed Ordnance Survey map when drafting descriptions of land in the purchase deed (e.g. sales of part).
A street map anywhere in the UK