The first thing to do is to carry out a search at the Land Registry based on the address of the property. Help from a solicitor will enable you to do this.
The Land Registry has a website which does also have public access facilities.
In the case of unregistered land, it may be more difficult to locate the freeholder by a search of publicly held information and it may be necessary to serve an information Notice under the leasehold reform legislation.
For further assistance with this please consult a professional.
Tip: Your freeholder’s address and detail should appear on the ground rent demands as this is a legal requirement in accordance with the provision of Section 47 and 48 of the Landlord and Tenant Act 1987.