Integrating foreign ships in a surviving British Empire

How could a British Empire that never decolonised integrate second-hand American, Russian, Japanese, Chinese, and other foreign ships with a fleet using standardised imperial weapons?

Separate ammunition supplies are manageable, while commanders would coordinate different doctrines by assigning each group roles suited to its training and strengths.

The scenario combines an empire that never decolonised with common weapons across British and colonial fleets. Its proposed standardisation gives ships in each role the same gun family, such as 4.7-inch destroyer guns, 6-inch cruiser guns, and 8-inch heavy-cruiser guns. Imported ships could still use separate ammunition stocks, just as historical navies supported different calibres and several shell weights within one nominal calibre. The Royal Navy's early, Town-class, and postwar 6-inch weapons provide a specific example of successive shell types. The discussion also counts three varieties of 4-inch gun, four of 4.7-inch, and two of 4.5-inch. Maintaining British and American 6-inch ammunition lines would therefore be manageable alongside the variety historical navies already handled. Doctrine is the larger obstacle because allied crews can approach the same mission differently. Commanders could assign anti-submarine screening and carrier operations to groups already trained for them, then coordinate those groups under a common plan.