From 1909 to the present day.

Group Medal 1977, Close up

These crosses cover all awards from one to eleven years.
The brighter bronze and gold crosses shown have been produced since the late 1980's. The silver crosses have been consistent since 1976.
The ribbon changed in the late 1990s from the narrower central green stripes (as on the bronze and silver crosses), to broader stripes (on both gold crosses). This was done for ease of manufacture rather than to reflect any change in the full size ribbon.

KNBLO Small 40-60 (Common R)
KNBLO Small 40-60

These crosses are for forty, fifty and sixty marches.
Each of these minature crosses was introduced when the full size medals were first awarded.
The reverse side is common for all these medals.