Will Muslims say no to P&O?

I was booking a P&O cruise for a client late last Friday when he asked me if P&O would be ok to serve him and his wife Halal, (food suitably prepared for Muslims), food on the cruise. Assuming this wouldn’t be a problem as I had done the same with other cruise lines I went ahead and booked the cruise for him.
Calling P&O first thing Monday morning to add the request I was shocked to discover this wasn’t a dietary request they offered on any of their ships.