Here is the British parts manual showing a BREN spare barrel as an assembly number with individual internal components and external bracket.   While the TL part number sequence is similar, the bin itself by this period (1944/45) is different.  The bin applies to the three MK’s of British produced universal carriers.  
 
If Luca could find a date, it may shed some light on the application.  I am thinking earlier that the introduction of the universal series.  
 
.
		 
		
		
		
			
		
		
		
		
		
		
		
		
	
	 |