Its not a hill I am going to die on and I respect the ideaThere are never ‘enough’ rounds but the Bren was the principal section weapon and having the riflemen use the same round adds to the possible resource to draw upon. Not to mention the reloading Bren magazines from the bandoliers carried by the riflemen, from which they reload their rifles. Having said that the Sten was replacing some of the rifles later in the war.
The comparison British use of Mannlicher en bloc or Mauser chargers is the cumbersome nature of the Mannlicher in a cloth bandolier compared to the thin Mauser chargers. The Americans kept their en blocs in their webbing, but then they did not have pouches full of Bren magazines. Individually I prefer the Mannlicher mode but the British army was Bren lead and demanded the pouches be full of Bren magazines (and grenades) so needed a thin charger for the rifles so as to be able to wear the cloth bandolier as the standard reload resource.
Later, with the L1A1 and L4, they could use each others magazines. There may be a lesson in that. With the L7A2 I recall much filling of ‘57 Pattern pouches with coiled GPMG belts as the GPMG reserve supply and ending up with reloading magazines in the field from chargers in cotton bandoliers and squeezing magazines into pockets.
Its just that the Bren gun Mags are incredible - in some respects some of the best magazines of the war
However as I said it was heavy - the Vickers Pederson rifle is already 9 pounds adding a Bren gun mag is going to make it
My understanding was that one chest pouch was for 2 x Bren gun magazines - the other for ammo clips, grenades, bars of nutty....and Sten gun Magazines could fit in them as well.
Perhaps if combined with the para smock dedicated pockets could be used for clips?
Of course the final design of the 37 webbing was not arrived at until after the Bren gun was adopted and the Pederson was not - so the layout etc could be adopted and changed accordingly.