Hi Barry
Sorry, I don't know the different pattern numbers so that doesn't mean much to me, but it does look very similar in style to the pre-1921 RNR and RNVR cap badges, with a more rounded look to the wreath than the wider WWII style badges...if you know what I mean.
I've attached a couple of pics to sort of illustrate my point. It could be they used the RNR/RNVR style badge template as a lot of MN officers were in the reserves?
Very interesting topic, it would be great to find out more info, so thanks for bringing it up.
Cheers,
Alex