Hello 🙂
There will be at least one (hopefully more) vegan option per course in the Freedom and Club restaurants (the included MDR).
Don't worry, you will not just be stuck with lettuce, them is also some vegan options in the buffet and P&O are now labeling which wines are vegan in the wine list.
Some examples of vegan items I saw in the MDR (Freedom and Club restaurants) :
Starters: Radicchio, Orange and Fennel Salad, Salad of Caramelised Apple
Main: Pumpkin and Courgette Noodles
Dessert: Dark Chocolate and Olive Oil Marquise
Furthermore, in the MDR I recommend that you ask the Head Waiter to see the menu for the next day and if you do not like any of vegan options, they can prepare a modified version of the other dishes or something to your liking. They are very accommodating 🙂
Unlike Arvia and Iona, some speciality restaurants (Extra costs restaurants such as Sindhu and The Epicurean) on Azura do not have a vegan option in the menu but if you ask the Head Waiter at the speciality restaurants a day in advance, I am sure that they will try to accommodate you and try to find something suitable.