The Landlord and Tenant Act 1954 protects tenants who occupy their premises for business purposes. You can contract out of it, but only if you get the paperwork right, before you or the tenant are legally committed to the tenancy.
You can easily create a business tenancy by word of mouth without anything in writing, perhaps without meaning to. Consequently, you cannot get the tenant out without six months' notice. Even when the notice expires, the tenant may be entitled to a new tenancy, unless you can oppose this on the limited grounds set out in the 1954 Act.
Even a written agreement to give a tenancy for a fixed period will not mean what it says unless the 1954 Act is contracted out of by the correct procedure. If the tenant does not leave at the end of the period, the tenancy may continue until you end it by six months' notice - and the tenant may be entitled to renew it even then.
So, come see us at the outset and tell us all about the deal. We will tell you what we can do for you and how much you can expect it to cost.