Double breasted or center fastening?

[Paullus Scipio]

This is exactly my point; the equipment looks Hellenistic and Roman and matches no Classical or Alexandrian Macedonian depictions or artefacts yet found. The Persian depictions also do not match Achaemenid styles.

This seems a very odd statement to make to me - and demonstrably wrong !....and I speak as someone who has intensively studied Greek and Roman Warfare all my life, and formally for almost 40 years. The equipment - of which very little is actually visible- 'fits' what we know of the late 4 C BC exactly, down to details which would not be generally known in the 1st C BC, nor is the Achaemenid or Macedonian equipment any different from that shown in many other late 4 C BC depictions, and dateable archaeological artifacts.

Actually there is an enormous amount of doubt about this in academic circles. I have spent a lot of time talking to Dr. Stella Miller Collett about this subject.

I very much doubt 'enormous doubt', especially if you mean among those who know about Greek and Roman equipment rather than just 'academics' who actually don't know much about the subject. Like Ruben, I would be curious to see this paper ( singular, I notice! ), if you can produce it, since as far as I know, a 4 C BC or earlier example can be found for every artifact portrayed in the mosaic, and Ruben has made an excellent start, to which one can add the Tube-and-Yoke corselets of Darius' guard, paralleled by 4 C and earlier Achaemenid depictions, the sword in the foreground, matched by finds in the 'Philip' and other Macedonian tombs, the 'knobbly' javelin paralleled by depictions in the Kazanluk tombs, the horse harness details generally, the 'leopardskin' shabraque, Darius' clothing - and that is just for starters ! In fact the artistry and accuracy of detail are quite remarkable and easily sufficient to identify individual items.