1980 Elizabeth II Queen Mothers 80TH Birthday Commemorative Crown Coin. In 1980 to commemorate Queen Elizabeth the Queen Mothers 80th Birthday the Royal Mint struck a limited issue commemorative crown coin. The reverse designed by Richard Guyatt has the Queen Mothers head in the centre with a fanfair design with Queen Elizabeth the Queen mother August 4th 1980. The obverse is the portrait of Her Majesty Queen Elizabeth II by Arnold Machin.