Hi John,
I've taken onboard what Brent mentioned and have tried 'exploding' the photos of your badge but am unable to see any RD Number on the reverse of the trumpet horn. Does it have one?
Also, your badge quite clearly shows what I'd describe as the correct void space on the crown whereas the badge Colin showed in his original post merely had what appears to be 2 small holes drilled in the crown. In part that is what led me to believe it was a copy when he and I discussed the badge. (Colin's badge did appear to have a RD number though, but I was unable to discern what it was).
All-in-all it's a bit of a minefield, especially when it comes to the uncommon (and therefore hard-to-find) badges
.
Regards,
Lovat