Superb 1916 British Officer's Trench Whistle With Dated Strap

An exceptional and possibly an un-issued 1916 dated British officer's trench whistle made by J.Hudson & Co of Birmingham, what sets this whistle apart from most others is the superb condition leather hanging strap bearing a minute War Department broad arrow mark, a letter 'M' and a 15 (1915) year date.
I have acquired many whistles over the years but very few with War Department issue marked straps.

Code: 50992