A Stamp For 007? A WWII Forgery For Spies Of A Dutch Stamp

I have in my collection an unwatermarked forgery of Netherlands 172 (NVPH), the 1 1/2c gray flying dove of the 1926 series (with watermark circles). This clear forgery - it's the stamp on the right - was produced in London by Waterlow & Sons for British Intelligence during WWII. It is thus an official forgery, and is listed under NVPH 172Ba.
It is not clear (to me, at least), precisely what the British had in mind for this stamp. Opinions are divided over whether it was ever actually used - the NVPH claims it wasn't. It's not one of those propaganda stamps lampooning the Nazi's either.
Did the Brtish forge one or more stamps of other occupied nations in the same way. Can anyone tell me where to begin if I want to research the use of (forged) stamps for espionnage? Thanks!

The CIA has this little piece...

https://www.cia.gov/library/center-...04i3a06p.pdf

Hunting around on internet, I found this lengthy, detailed article, with some useful references: Propaganda and espionage philately; http://www.psywar.org/stamps.php. It takes the forgery a bit more seriously, but I wonder how much of it is pure guesswork.