"The Immortal Battalion" and "The Way Ahead" are essentially the same film.
The latter was the version released in the UK; the former was edited and then distributed in the US. The major difference that I recall was the handling of the story of a member of the platoon, whose wife was having an affair. In the original, the solider went AWOL and his platoon commander (David Niven) and platoon sergeant tracked him down and then brought him back after they stood guard while he beat the crap out of his wife's boy friend. They then went to bat for him and were able to get his time in the digger reduced because of the circumstances. Perhaps because of Hollywood's moral censorship, the incident did not appear in the US version.