Okay - am looking at some Cam Kennedy Norties here. The hoses are coming in much closer to the mouth area and he's given that area a bulge similar to a hospital oxygen mask "cup" so it looks like there's a single breathing unit there with no obstructions.

He also keeps the rear cylinder simple - it's just a single cylinder with the pipes connecting at the top with a small circular thingy that might be a valve of some kind. Ah, okay, there's a few guys with the Gibbons 3 Cylinder combo pack but they have slightly different patches on their shoulders, so they're like part of a different team within the Nortie forces or something - long patrol maybe so they need more air storage? While the single cylinder dudes are short-duration shock troops?

The vehicle design is still pretty basic here - I know it picks up later so I'll have to check later stories.

Cheers