The only date that can be said to be “key” is ** 1952 **. These are very common in VF, but difficult to find in mint state.
** 1952 George VI Sixpence **
1951 George VI Sixpence (PROOF)
1951 George VI Sixpence
Slabbed and graded LCGS 85 (Choice Unc – BU)
1951 George VI Sixpence (Duplicate)
1950 George VI Sixpence (PROOF)
1950 George VI Sixpence
1949 George VI Sixpence
1948 George VI Sixpence
1947 George VI Sixpence
1946 George VI Sixpence
1945 George VI Sixpence
1944 George VI Sixpence
1943 George VI Sixpence
1942 George VI Sixpence
1941 George VI Sixpence
1940 George VI Sixpence
1939 George VI Sixpence
1938 George VI Sixpence
1937 George VI Sixpence (PROOF)
1937 George VI Sixpence
Encased Farthings 