I'ts always worth a rummage!
I managed to find a DPM Ventile (SAS style) smock, in an army surplus shop in a box full of trashed DPM combat jackets marked (i think) any Jacket £7!
sadly it had no label or markings at all but I assume it was made by "SASS" or perhaps "RADAR", it's old and a bit worn needed to fix a couple of holes but works amazingly, has identical features to any standard SAS/Arctic smock (nothing extra) so difficult to say exactly where it came from, but as you'd expect it is soft when dry and stiffens almost like cardbord when wet, comfortable to wear as a shirt and outerlayer!
the moral of the tale...always check the bargain bins in surplus shops!
BTW, when I bought it I didn't realise it was ventile i just knew it was different I then had to Google the oddities about the fabric.
It first caught my eye because the "black" of the DPM looked odd, almost like it was everso slightly shiney almost as though it was a different sort of ink or it had had been added later. Also the print can't be seen on the inside of the fabric, I later found that there is a technical reason because it's difficult to print on ventile.