WW1 Boys Brigade Edinburgh Rest Hut 1916 to 1919 workers badge

A very rare original 1919 gilt metal presentation lapel badge, bearing the Edinburgh Arms with "Nisa Dominus Frustra" (Expect the Lord in Vain) motto above. Very good condition, original buttonhole fitting, an excellent example.
Height 34mm.
Presented to Boys Brigade officers who staffed the Soldiers and Sailors huts in Edinburgh during the First World War.