Unidentified Naval Buckle

[bananamafia]

Hi guys i dont really no where to put this post, but any help on this naval buckle would be greatly appreciated.
marked to back with MARTINS PATENT.

[paulp4180]

A quick look around I found this:

Martin patented belt made in England - info needed | Collectors Weekly

https://worldwide.espacenet.com/publ...C=GB&NR=660336

Very Rare Martin

Port Line Martin Patent Nautical Expanding Copper Belt c1940s

I think its probably more commercial rather than military, but I could be wrong?

[Ubique]

I would not be surprised if it was late 1800's. Similar buckles are often shown on metal detecting forums.

Oz.