Get a value-brand kettle, teapot, mugs and a tray, and 24 value-brand teaspoons. Explain that the mugs are clean and it's up to them to wash them. Like the toilet you have dedicated to their use for the duration.
Show them where they can fill the kettle and wash up.
Provide hot water, sink, drainer, WUL, brush, kitchen roll, bin; unless you are going to wash up for them (I don't recommend it) and tell them that if they bring you the tray at the end of the day, you will wash whatever's on it ready for the next day (you will not be hunting round for mugs growing green mould that they've put down somewhere).
Provide a biscuit-tin with PG Tips teabags, jar of Nescafe, and a carton of fresh milk. Provide one carton a day.
And a box of cube sugar. This is important. Granulated sugar they will spill and trample to attract ants.
Do not provide bacon rolls.
If you feel the need, provide one pack of biscuits per day, on their tray. If asked, say you unfortunately have no more.
Do not allow them to touch your hoover. Take it apart and distribute the components between the locked garden shed, the boot of your car, and under your bed.