I have identified five different back types, many with variants too many to list here, but the basic five backs are reproduced here:
Type 1 -
Norman Helmet. So far found
postally used between 1914
and 1948
Type 2 -
Postally used between 1928
and 1984
Type 3 -
Postally used between 1939
and 1959
Type 4 -
Norman Helmet, postally used
between 1940 and 1991
Type 5 -
Helmet, postally used between
1959 and 1997
SHOESMITH & ETHERIDGE -
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