The Jethro Tull album "Warchild"was released in October 1974 (before the fight?), The Clay/Foreman fight was October 30, 1974.
If it is connected to the fight, which is the chicken and which is the egg?
Other than the use of the word jungle, I don't see a reason to connect the song to the Ali-Foreman fight. The lyrics have nothing to do with boxing and seem to be some sort of vague narration about tourists and/or colonists in some unidentified jungle who get drunk every Friday and scoff at the "monkeys who live in their dark tents" (presumably representing the natives).
Bungle means to behave clumsily or foolishly. It seems to be a song about people behaving foolishly in a jungle, which may be literal or metaphorical. I don't have a more concise or definitive interpretation than that, but I can't see anything that would connect the song to a heavyweight championship fight.