1. is Tea and coffee available free in the buffet?
Yes
2. I have heard that supplies of milk, tea and coffee in the cabin can be somewhat frugal. Would I be able to bring a carton of milk and my own tea and coffee on board?
We just get extra milk, tea and coffee from the buffet and take to the cabin, but yes you could also bring your own.
3. when I booked with P and O, I asked about gratuities, and was told that they aren’t required, which surprised me. It may be because I booked in Australia, where there are laws about compulsory gratuities. What do most people tip for cabin staff, drinks service, and waitstaff?
Tips are also included with P&O in the UK but some do give a small extra tip at the end of the cruise to their cabin steward and waiters if on fixed dining.