Apologies, for no good reason I didn't twig your location.
I can't vouch for the stuff first hand. There's a good write up on Sniper's Paradise. I've been toying with the idea of getting some for a while.
Sounds as though you'd have the same reticence as me!
It's occurred to me that I haven't given you the easiest most uncontentious solution:
For really quick excellent cam, that is 100% easily removable try Brit sniper tape (it's actually name tape for NBC suits, but has come to be known as sniper tape, you won't see an L96 that isn't covered in it. Comes in pale green or sand:
eg ebay link: British Desert Sniper Tape
Put it on and then muck it up a bit!