Although I know to expect it - I did complain to BA about the offering and misleading information on their site, they got back to me with this new reason as to only being able to offer a roll.

"Our catering supplier had unexpected problems with the system they use to deliver our catering. Our Operations team made the decision for your flight to depart without our full catering service on board, to avoid any further delay to your journey."

I don't understand why they just can't tell the truth....