Understand the difference between freehold and leasehold: The contract you get on the purchase of your property may state that the property is freehold or leasehold. Freehold ownership is much easier than leasing. If you buy a freehold property, it means you own the building and the land and boundaries on which the building sits. As long as you abide by the law, you can pretty much do whatever you want within reason. This applies to most properties in England and Wales.
If you buy a property on lease, then this is a completely different pot of fish. You will find that you do not have the same rights as a freeholder and you only buy the right to live in the property for a fixed number of years, but the land belongs to someone else. The lease normally has a period of time. Many have lengths from 99 years to around 999 years. After the lease expires, ownership reverts to the landlord.
Most mortgage companies will not give a mortgage if the lease is too short, as they then have no protection. You will find that because the landlord retains ownership of the land and the building, an annual service charge will be levied for the upkeep of the building as well as rent for the land.
When it comes to conveyancing, freehold ownership is much easier to do. However, leasing can be a little more problematic, and remember that most flats and apartments in the UK are actually leased. If the lease is for at least 40 years or more, most mortgage companies are happy to lend on the property, but will rarely lend on shorter leases. The things to look for in the transfer are hidden clauses and fees that could affect the value of your investment, as you want to ensure that you can live in peace throughout the term. Make sure your lawyer is good and specialized in this field.