Hi,
Your first carrier is very nice indeed.
None of the fitments on the second one look British, even for post war service. It looks more like a mixture of US webbing and French canvas. I suspect it's a British frame refurbished either by a European power postwar. France, possibly? Remember they used a lot of WW2 equipment in the 50's in Vietnam, leather would not have lasted long there.
Or a frame built up by a military dealer out of webbing he had in stock. This is not unusual, you often see US musette bags sewn into pairs to make saddlebags for bikes, etc.
Best Regards,
Adrian