Dear Mary: How can I make my slobbish flatmate pay for a cleaner?

Q. My godmother owns a house in a great part of London. She does not come up very often and she is very kindly allowing me to move in for a year with three university friends. I will be landlady and collect the very low rent she will charge us. It is amazingly kind of her so I am annoyed that one of my intended lodgers, who has never even met my godmother, but will benefit from her generosity just through being a friend of mine, refuses to contribute towards a cleaner. He says it will be a waste of money for us to spend, collectively, £120 a week (£30 each) on a cleaner, because we could spend that money giving two dinner parties a week instead. None of the rest of us wants to waste time cleaning and I know this friend to be a major slob, so how can I resolve this without falling out with him?
—Name and address withheld

A.