in occupation? Grand-daughter lives in a flat and landlord regularly comes to inspect and make personal remarks about untidyness. She and her boyfriend are good tenants and have been there for 3 years. Does the Landlord have that right?

They should give you 24hr notice and you you are allowed to be present. They should still knock too!!

Get them to check their lease. I'm pretty sure that under a standard lease he has the right to inspect the property but it has to be at a pre-arranged time. If there is a clause in their lease that allows him to pop in whenever he likes then I would be getting a new landlord.