G'day hart, the Deckson Eagle usually had a chrome tank, red frame, 4 speed gearbox, a largish chrome wire type heatshield on the exhaust and smaller but fatter tyres than most minis of the same era. The motors looked very much like the Gemini's of the same era, cast iron cylinder, up pipe on the right side small carb. Some were fully registerable and there was an Eagle 80 MX with no lights. Finding pics of these bikes is hard but my bro had one back in '74/'75ish and I remember it well. White piping on the seat trim, red stripe down the middle of the tank, chromed steel guards, white walled tyres. A good looker and also good for a genuine 6omph. I'd say if it has a swingarm, if it's an 80cc and has 4 speed then it would most definately be an Eagle 80. All the others were based on rigid frames centrifugal clutch Kirby or Victa type stuff
like near all obscure and non loved models the Deckson Eagle today is as rare rocking horse poo and there are collectors who'll pay $$$$. Thers actually some Eagle parts on eBay, maybe take a look and see if the bits look like they'd fit your model.