One thing I have noticed is that in my original picture the Cadet is wearing the first pattern badge, as shown on the left of the attachment. Most of the other pics seem to show the second pattern, as shown on the right of the attachment. Maybe the original intention was that they would wear it at the bottom of the sleeve and this later changed to the upper arm, to distinguish between Master Aircrew (WO) and the others???? Please ignore the star colours as there were two types according to category. The eagle is different on each version as well as the background colour change.