Why the Far East command needed naval political weight

Could Lord Gort have commanded a combined Far East command?

Not realistically; the Army had other priorities, and a senior naval officer had the best chance of carrying the political authority needed to unite the theater.

The Army was absorbed by the defense of Britain and the campaign in North Africa, so it did not want responsibility for the Far East. The RAF likewise had not assigned one of its strongest operational leaders to the theater. The Navy was therefore the service most likely to provide an officer with enough institutional and political weight to coordinate the command. Such leadership could also have pressed the case for earlier fleet carriers or accelerated Unicorn-type construction.