The short version
The china associated with Titanic and Olympic was not a single uniform dinner service. White Star Line used multiple patterns by class, room, vessel, date, and service type. Some patterns were ordinary company service wares shared across the fleet; others were special, costly, and much harder to place with certainty.
The familiar first-class “Wisteria” pattern is strongly associated with White Star’s Olympic-class service, but the name itself is a modern collector shorthand rather than a confirmed contemporary pattern name. The cobalt-and-gold Spode services, especially R4332, belong to a much narrower and more attribution-sensitive category: prestigious, scarce, and closely tied in surviving evidence to Titanic.