Frank, that is a question I am very interested in, as my uncle (R.C.A.F.) has in his group a GVIR CD. When I got his service record it states that he was awarded the Efficency Medal in 1934 (He had some Militia service with the Queen's York Rangers before joining 110 Squadron, later 400 City of Toronto). My late aunt remembers him having a yellow and green ribbon, but the group is as he wore it (WM, CVSM, EIIR Corontation, CD). Nothing in his service record about the award being cancelled. There was another Bill Hamilton in the Squadron, but he was permanent R.C.A.F.
His service records vary as to his Militia service - I would think that to have qualified in 1934 they must have counted his cadet service.
I've been tempted to apply for a replacement, as my theory is that he got the ribbon but was never issued the medal.
Michael
Should have waited for the email notification............
Larry