I am just archiving some old tape recordings to computer, and have just heard the late, lamented Frank Muir singing this song!
I had heard the 'Hot Shot Dawson' theory advanced somewhere, but can't remember where.
Incidentally, at the time of the song, Swedish was used as a funny theme in the Navy version of 'Calling All Forces', in which Eric Barker took a similar role to Kenneth Horne (RAF) and Charlie Chester (Army).
They featured a Swedish Masseur, voiced by Jon Pertwee, who used similar nonsense words, and could only be understood and communicated with by Pearl Hackney. He usually eventualy came out with an angry outburst of ' Deborndits, Deborndits, Jeden, Jeden, Jeden!' as he pounded Eric Barker into shape.
Pertwee said that he had listened to Swedish radio broadcasts, and the word 'jeden' came up so often he figured that was the only one he needed.(think it means every!)

FC