Hi Jon, I was following Jerry's train of thought when I found the NAAFI thread and also a shield badge on Sally Bosley's site.
https://www.sallybosleysbadgeshop.com/shop.php?ps=1#
After your post I also found a photo of what is described as " an officer's shoulder rank" in a lot titled "NAAFI Insignia Grouping".
http://www.homefrontcollection.com/photos/10300.jpg
Edit : Could the one on your slide be upside down , the two patches in the NAAFI thread appear to be a 'matching pair' (diagonal stripe L/R) ?
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