Hi we were recently onP&O and took an extra case with (we were not flying) which we fill with incontinente pants and also inco sheets, if you have not come across these yet the are a sheet about 600x300 which go on top of the sheet you lay on with an absorbent layer which you lay on and a water proof layer on the other side. We just bagged them up in the morning and leave them in the bathroom and they were taken away. Are you in a accessible cabin because this does help as the except this kind of thing. We didn’t have a protective cover but did ask for a done was provided. Hope you enjoy your cruise.