“They were known as Ordnance Q.F. 37 mm Mk 1 and used mainly by 3rd RHA and 106th RHA (Lancashire Hussars) within 7th Armoured Division, although some did also see use in Somaliland.”
From:
http://www.btinternet.com/~ian.a.pat...partillery.htm
LRDP units in Western Desert also used them, before switch to 20mm Breda guns.