The Tenant.

Put on your best Afrikaans accent.....

"I like people, but I would advise you....don't mess with me on the rugby pitch or I will kill you. Simple as that, man".

I don't bother inspecting the flat anymore, I just phone and tell him he's the best tenant I've ever had and, if he'd like me to, I'll gladly pop round and clean the flat for him.