If you are buying a flat on what is known as a cross-lease title (a cross-lease flat) you are acquiring a share in the land in common with the other flat owner/s plus the leasehold title to your unit for a period of (usually) 999 years from the date of the lease. This gives you exclusive occupation ownership of your unit, and the area of land allocated to it, but also means that you will have some joint responsibility for shared use of common areas (if there are any).
Check the common areas to see if any repairs are needed, as this could involve a big expense for you. If you have any concerns about the condition, get a qualified surveyor or a builder to inspect the property.
You should look at a copy of the flats plan that will be attached to the title. It is imperative that the flat’s plan correctly shows all the buildings on the land, especially the correct outline of buildings and the areas that you are entitled to use. If the plan does not correctly record what you inspected, it may be defective. Most defects are capable of being remedied but that remedy could be expensive. You need to discuss that with your lawyer.