✅ SOLVED Some sort of button, looked everywhere, cannot find it!

[Hunter.ryan]

Found this button today, looked all over the internet for it and cannot see it anywhere!

At the back I can see the word London but cannot make out the others. Given a try ( 2000 HR 5E LONDON C . NITSCH )
The front has a crown at the top and a little crown below on a lions head with writing under it saying something like ( ESSAYEZ )

Any help would be appreciated

 

[Hunter.ryan]

NOT SOLVED

 

[nhbenz]

I think the backmark reads "20 Cork St London" as well as "C. Nitsch" as mentioned.