Branch badge unknown

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Lantern Swinger
Hi All,

Been lent a set of square-rig by the unit for display at a recruiting event. The branch badge is unusual and nobody could tell me what it was, not found on Google either.

The badge consists of the letters 'DN' in gold, in a gold circle.

Anyone know what this is?

Yours aye,
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I am looking for help to acquire WRNS Dental Surgery Assistants badge (DSA) and also Dental Hygienists badge (DH), both in gold braid. Can anyone point me in the right direction. I have currently exhausted all know options on the internet. Thanks.