Hi Most Cruises will do there version of a full English some use American styled bacon and sausages but can recommend from experience Royal Caribbean and P&O both do a very good English in the main dining room and also its available in the buffet areas?
Most ships you can take breakfast in the main diningroom or go to the open service where you can help yourself so getting a full english should almost be possible given though most offer american style dishes. Usually available eggs in various options; bacon; sausages, but remember you are on a cruise to enjoy yourself and get away from some of the meals you might have back home.
Full English is available on most ships - remember if you are on a US line then the bacon will be the crispy American variety and not the back bacon you are used to here.
Just a little rider to the bacon at breakfast....If you ask for Canadian style bacon you will be able to get close to our back bacon as opposed to the American style of crisp streaky....Ida.