Bandmaster's badge?
 

Greetings all. I recently picked up this oversized badge, and I'd consider it too well made to be a reproduction. Could this be a Bandmaster's badge for a fur bonnet?

Mike it looks too big for the Bandmaster cap badge and is the wrong shaped background. The badge worn on the fur busby was exactly the same as that worn on the SD hat, although it is larger than a standard WO badge.
Dave

And there was only one size? Isn't it possible that it may have varied by manufacturer? Any other ideas as to what this badge might be for? I can't recall having seen an RAF/RCAF badge with an embroidered eagle that was not for the band

Yes there was only one size for both SD cap and Busby. I think this badge is spurious and, although well made, is a fake and definitely not an RAF badge. I came acoss a badge being sold by a US website said to be a WWII WO badge made for collectors. The quality was good but the design totally spurious. I think your badge is intended to be an Officers cap badge from someone who doesn't know better or it is a blazer badge for ex-officers.
Dave

Good morning, I have to agree with Dragon166 and just in case, I also checked Music in Blue by Gilbert Singleton and did not find reference to the badge mentioned.