Hi Mike
I did a little research over the net but could not locate any info regarding what the Bde(s) could of used.
However I did come across 8th Bn Kings Own Royal(Lancaster)Regiment-
Western Command-4th Malta Bde, and note they wore their own CST and FS(?). Maybe all the units followed suite and that the numbered Bde's used a standard Maltese cross on a shield at HQ level and the numbered Bde were just that on paper?
Malta Garrison 1942:
https://forum.axishistory.com//viewtopic.php?t=82303
Kings Own Royal Regiment.
http://www.kingsownmuseum.com/gallerywwtwo002.htm
Anyway you have raised a good point!!
Phill