Help dating this jacket! Royal Patent?

[boratetonic]

Never seen a tag like this before and would love some help dating this jacket, or any insight on what this tag might mean! Seems like repairs may have been made at some point. No other tags or labels and no engraving on the buttons. This has me stumped! Any help appreciated

 

[poppysvintageclothing]

The jacket looks 1940s to me. Let's see what others think.
Certainly is an interesting label.

 

[MagsRags]

I love the colors! They did a nice job matching the plaid too.

 

[Jonathan]

I suspect its wartime British - the lack of pockets, small amount of fabric for hemming, narrow collar, no cuffs... but I have never heard of a royal patent before...