I probbaly got a bit incoherent there ... I should emphasise that the rumour of a separate, older, "good honest English" source for Waltzing Matilda has lurked about since the end of WW II ... and been mulled over by a number of folklorists.
I believe it simply arises from the active parody instincts of soldiers in the interminable boring times between the moments of panic. Probably as a parody by English soldiers tired of Aussies singing Waltzing Matilda yet again! The later misinterpretation arise from quite common extensions of antiquity given to immediate ancestors' stories and songs.