UK Landlord Forum / Life

Hi all. New user here, so thanks in advance for your help! My tenant has been in our property for a little over 4 years. We had an initial agreement signed, but this has ran out and her tenancy has just continued (with rental payments happening). Now we want to sell, but unsure what steps I need to go thru to do this. We have a feeling she may be difficult to move on.....

Noting that I live in Australia and my property is in London.

Cheers