In real life, of course, the Burmese theater was harsh and terrible, and the Commonwealth forces in the British Fourteenth had no headstarts at all -- by the time it was formed, the Japanese had pushed almost to India, and almost the first thing it had to deal with was a massive Japanese offensive. The head of the Fourteenth Army, Field Marshal William Slim, wrote a memoir, Defeat into Victory, and the title summarizes exactly what he and the Fourteenth did. The stunning and very difficult campaign was one of the most important in the war. Yet, at the same time, the British Fourteenth became known as the Forgotten Army because the press hardly mentioned it -- this besides the fact that, by the end of the war, the Fourteenth Army was the largest army in the world. But the Pacific War would have gone very differently without Slim's brilliance and the Fourteenth Army's indefatigability; the Japanese became tied up in Burma to such an extent that they ran themselves into the ground there. Those were tens of thousands of men who would have been fighting the U.S. in the island-hopping campaign. Or, for that matter, fortifying New Guinea.
What brings this all to mind is that I am, of course, reading Noë Coward's Future Indefinite, and he talks about visiting the Fourteenth Army, and notes that troop morale was really hurt by the 'Forgotten Army' nickname.
In Comilla I lunched with General Slim and he talked, unsentimentally but with moving sincerity, of the Fourteenth Army. He referred with sudden bitterness to the phrase "Forgotten Army," which had been coined by some zealous newspaperman who was evidently more interested in mots justes than noblesse oblige. The general explained that although the morale of the troops had remained astonishingly high throughout all the vicissitudes of their repeated advances and retreats, this label "Forgotten Army" had really stuck in their minds like a prickly burr and hurt them out of all proportion to its actual significance. The trouble was that there was a germ of truth in it. They realised, when papers were sent them from home, that as far as news value was concerned the war they were grimly fighting year in year out was apparently not important. Columns were devoted to raids on European strongholds, to air battles and sea battles, but their exploits, if mentioned at all, were usually relegated to the back page. General Slim asked me if I could do anything ot remedy this situation when I got back to England and I promised to do a broadcast at the earliest opportunity.
[Noë Coward, Future Indefinite, Doubleday (New York: 1954) pp. 312-313.]
Coward would keep his promise.