Peter,
There is a discussion going on here in the US as to whether Bren Mk 1's were converted to Mk 3's. I did find a topic here that indicated there were some 1 to 3 conversions done at Ishapore (India). Where any such conversions done at Enfield?
https://www.milsurps.com/showthread.php?t=20594
The discussion started as to which Mks were converted to L4 7.62 Nato. "Bren Gun Saga" shows only Mk2's and 3's. Would one think that any original Mk 1's would have ended up being converted to L4's as 1's converted to 3's ?
Thanks ,
Joe