Whoa... if that's a MkVII it's not original at all. I don't see snaps on the flap, the rings on the side, or drain holes on the bottom (possible they're out of view but still)...
I don't know about that thing man. Hopefully Swindy or another bag expert will chime in here.
That is actually a civilian version of the bag. Many of those bags and mask were made for just about every member of the London population. Thanks to the Nazi's and their endless bombing of London. I can't imagine this bag/mask being anything else for that price.
