The crown on your head badge is indeed a "Queens" crown as opposed to a "Kings" crown, as detailed in the illustrations below.....
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This would have come into use, as
@3-speeder rightly says above, with the coronation of Queen Elizabeth II in 1953; it is still in use officially today and will remain so until Charles III (or perhaps William V) is crowned.
Although Charles may take the title as George VII.
Interestingly, the 1954 catalogue just shows this headbadge on the cover and throughout (VC-C library image).....
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.....so perhaps it was a one year only badge as you suggest
@3-speeder.