"E" marked Bren mag

Does this letter "E" have any significance that is painted onto the side of a Bren mag, please?

Thanks for any info.

E Company Perhaps?

Some Rifle companies did mark their accessories with painted markings. For inter unit ID & accounting purposes.
It would be easy to ensure that their totals added up. After an Exercise Etc.

Most mags I have seen marked, have been done by an individual. Who had 'acquired' his 'Own' over a period of time.......
& usually a cleaning kit & sling as well.

These were marked/ painted to his own design/ taste. To enable identification of 'His' items. Usually, the reason these were
'Acquired'. Was like a lot of things, that helped save time. On the return to Barracks on handing in weapons & equipment.
If The individual had everything of his own, & ONLY His Personal Weapon signed out on his charge. Then simply handing in
The weapon after ensuring it was clean beforehand (Usually!) was a quick task.

But on a section/ support weapon such as the Bren/ Lmg mags. I would say in my opinion it was a company armoury thing.