The pack shown on the photo is a Bergen, not the small pack as described in the text. I believe either would be correct for a Commando impression.
Yith will shortly chime in re: windproofs.
5...4...3...2...1...
lol... Except I know very little about windproofs. I don't own any for a start. It is a hole in my Brit collection... One that won't be filled in a hurry as I don't really like them!
From what I understand late in '44 they were issued en masse to several divisions in NWE. Before then they were much rarer and only used by who could get hold of them.
They're designed to go on top of BD and being cotton they get VERY sodden in rain.
I know nothing about how good the SoF one is. I do know that replicaters ones fade to a nasty pink shade so avoid those. The one Gadge has on in the kit guide is a panzerfaust one and he really likes it, though the sizes are VERY strange with those.
The pack in the commando kit guide is a Commando Bergen. There are many patterns and types, but that one is an early original one. The one I have is a post war civilian one.
Ive commented on these before and while the Panzerfaust Windproofs are regarded as the best available of a limited choice(no idea of the SOF ones) personally i do not like them and would rather do without.As i said compared to others available they are the "best" but again only my opinion here(loads of people are happy with them)are that compared to my originals the material is a horrible plasticy,nylon type material that sounds like you are wearing a 70s/80s cagoule and the sizing and fit are terrible 
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Plenty of people are happy with them but no matter how much i try i just cannot bring myself to like them im afraid-sorry.
Im just kicking myself that i sold my original WW2 dated smock a while back for not much money 
