Tenure and title define what you are buying. Freehold gives you ownership without a time limit. Leasehold gives you ownership for a set number of years. Confirm the tenure in writing before you make an offer.
Check the title. Your lawyer should confirm the registered owner, any mortgages or charges, caveats and easements. Anything that restricts use or transfer should be understood before you commit.
Confirm planning and approvals. Check that the building or extension complies with approved plans, and that any alterations you see have the necessary permissions. Unapproved works can create problems when you sell.
Understand encumbrances. Some properties have rights of way, shared facilities or restrictions that affect how you use the land. These are easier to address before purchase than afterwards.
Use a qualified conveyancing lawyer for these checks. An agent can guide you through the process, but the legal review should come from a lawyer who acts for you, not for the seller.