I think an easier way of looking at the different Constructicons is with a timeline:
1985 - First release, green and purple (Gen1 global release).
(see here for example - http://www.tfu.info/1985/Decepticon/...devastator.htm )
1991 - Second release, yellow and purple. (European release only, including Australia)
Figures were not intended to combine, so most had parts removed that were redundant. Even though they were of the European line of Transformers, they are still considered Gen1 (or Euro Gen1).
See pic here - http://www.geocities.com/soxerboxx/z...wconstruct.jpg
1992/3 - Third release, yellow and purple. (Gen2 American release, but not in Europe or here)
1992/3 - Forth release, orange and purple. (Gen2 American store exclusive (Kaybee), but not released here)
Example of the third and fourth versions can be found here - http://www.tfu.info/1993/Decepticon/...devastator.htm
(click on each Constructicon to see their yellow and orange Gen2 versions)

And this link details the differences between the three non-European Constructicon teams.
http://www.geocities.com/futuristgro...tml#devastator
The website mentions the European set here:
http://www.geocities.com/futuristgro....html#g1europe

(note that up until the Transmetal year of Beast Wars 1997, Hasbro Australia was under the jurisdiction of Hasbro UK, which meant we *mostly* only got what was available to the European market.)