It's not proof, but I brought these back from my time working in Nepal in 1991/1992. I was actually working for the-then Royal Nepalese Army, but lived in the BGN Compound in Kathmandu. The sign and Union Flag were worn by the ex-British Army Gurkhas who worked as BGN's civilian security personnel. The sign also featured on letter headings and signs etc. I can't identify the second sign you posted.
British Gurkhas Nepal_c 1992.jpg