Leasing a property gives you the right to use the property. However, while you are buying this right to do so, it virtually stops there. That's because you do not own the land in leasehold. And you can only use the property for a fixed number of years. After the expiration of the leasehold, the property goes back to the landlord.
On the other hand, a freehold is more straightforward. You gain ownership of the building property, the land and its boundaries. Nevertheless, if you decide to go with leasehold make sure you get a long term lease of at least 40 years because this is a requirement in order to get a mortgage loan.
Take note too that you have to pay an annual service charge to the landlord as well. Nevertheless, you get to use the property so you also get something for your expenses. If the lease is long term, you also enjoy whatever improvements or structures you build there.
In contracting leasehold though it is important that you seek the help of the conveyancing solicitor. Not only will you get appropriate advice on the terms and clauses of the contract, you will also be able to have a faster transaction.