Would surviving First World War ships stay in service?

Would surviving First World War capital ships be retained for convoy escort if a European war followed the conflict with Japan?

Possibly. The choice would depend on the later war, how many replacements had been built, carrier availability, and whether the old ships consumed too many crew for the value they provided.

The comment argues that disposal takes time and that surviving First World War ships could still escort convoys in a later European conflict. Retention would depend on the strategic situation and on how much newer construction the earlier war produced. More available carriers could reduce the need for old battleships, while their large complements could make them costly crew consumers. An old ship's remaining mechanical life was only one part of a wartime retention decision.