General Post Office GPO Royal Mail postmans security badge

A very scarce original post 1979 'General Post Office postmans security badge'; large yellow chromium plated example, wide red enamel band top inscribed 'Royal Mail' postmans identification number '90' centre and blue enamel band area code 'NR' (possibly Norwich) below; the reverse impressed with maker's post 1979 details 'Manhattan Windsor' and stating that 'A Reward Will Be Given To The Finder Of This Badge On Handing It In At The Nearest Post Office'. Very good condition, complete with two loop fitting bar to reverse together with securing pin, no damage to the enamel, flaw on photogragh only.Height approx 44mm.