LONDON, Royal Mint, Plating Trial, c. 1970, in conjunction with the British Steel Corporation, in chromium-plated steel, rev. hour-glass shaped flask, 23mm, 4.96g (cf. Tansley 475); Special Trial Design, 10 Units, c. 1970, in aluminium or white metal, 23mm, 4.30g (cf. Tansley 479) [2]. About extremely fine and better £80-100