Cryhavoc101
Donor
Lionel Wigram, one of the main proponents of battle drill and basing training on operations research result, after experiencing combat in Sicily and Italy recommended that the Bren effectively be made a platoon weapon firing in support of the riflemen from a distance, as they tended to lag behind the rest of the section and not be available when needed during an advance (being 9-10x heavier than the M1 Carbine sans ammo and extra barrel was the major reason there). So I'm not sure more Brens was the answer for the British squad/section, as much as a reorganization of the platoon into specific roles (LMGs using their range from the rear of the platoon, riflemen using their maneuverability and speed to carry out the assault); the Germans started adopting that model of squad too when they could get enough StGs to equip the riflemen with.
Subsequent history shows that in practice dedicated 'heavier' automatic weapons were retained at Section and Squad level through the cold war and beyond.
It is only recently that we see lighter automatic weapons displace them.
A loaded Bren = 11.5 KGs - the reason for its adoption was to provide a mobile Machine gun that could maintain a relatively high rate of fire compared to the Lewis gun which while only slightly heavier was far far more difficult to reload, move and maintain and did not have a QC barrel.
The 1938+ British Section was effectively 9 Riflemen supporting a Bren gunner - their entire organization and equipment (chest pouches etc) was dedicated to it
I note that the NATO squad or Section throughout most of the cold war retained the 'heavy' GPMG (FN MAG/M60/MG3) and in some cases a second LMG (Royal Marines retained the L4 Bren gun at Section level) and later on we see the twin fire team setup with 1 FN Minimi in each fireteam and they are about 8 or slightly more KGs loaded.
While MG42s were initially removed from German sections armed with STG44s my understanding is that they soon made a reappearance - it was the same story with the US Army introducing the M1919A5 down to Platoon and section level and post war attempting to provide Squad level firepower with the M14 and heavy barreled versions of that weapon (M15?) and the Canadians using the C2 heavy barreled C1 (FN FAL) - in both cases ultimately the GPMG was adopted at Squad / section level.
So maybe a second weapon is not required here if the No4s are replaced as the M1 Carbine would provided greater sustained firepower and more ammunition for both the Carbine and the Bren.