Conveyancing is transferring the legal title in a property from one person to another. It is up to the buyer to make sure that they have obtained a good and marketable 'title' to the land, which just means they must ensure that the person selling the house actually has the right to sell it and there is no factor which would impede a mortgage or re-sale.
A system of conveyancing is usually designed to ensure that the buyer secures title to the land together with all the rights that run with the land, and is notified of any restrictions in advance of purchase.