Why a Royal Navy saint class was unlikely

Would the Royal Navy plausibly name an entire capital-ship class after the patron saints?

No; isolated saint names were possible, but a full class would be culturally and politically out of character.

St George had appeared in Royal Navy service, but occasional examples did not establish a tradition of whole classes named for saints. St David had a much narrower ship lineage, including a 1667 vessel and later tenders. The interwar navy retained strongly Protestant and Church of England naming traditions even though its officers included Catholics, Jews, and Hindus. In that setting, an entire class of saint names would have appeared conspicuously Catholic. St Patrick also raised the political problems of Irish independence and partition.