How the Royal Marines handled non-Commando personnel

What happened to Royal Marines who could not complete the Commando course after the corps adopted the Commando role?

Most qualified; those who did not could move to staff duties, retire, or transfer, while postwar demobilization and force reductions absorbed much of the issue.

Before the full Commando identity, Royal Marines served in ships' detachments, gunnery roles, port defense, and mobile naval-base organizations rather than a simple infantry-battalion structure. The high qualification rate and postwar reductions meant the remaining personnel cases could be handled individually.