The version I recall (1960s - in Junior school)

A sol, a sol, a sol-dier I will be
Two pis, two pis, two pistols on my knee,
I'll fight, I'll fight, I'll fight for the old country
I'll fight for the old count, fight for the old count, fight for the old country.

Fight always ended up pronounced as 'fart'

The tune we used wasn't quite Eine Kleine Nachtmusik, but there were similarities

Walrus.