Native Messaging: Python programme executes all lines but does not run any 'subprocess.Popen()' lines

Sure enough run() was exactly what I needed. The part you quoted is also highlighted in the docs and I still went out of my way to overlook it, I truelly am my worst enemey.

That article you linked to was really informative on the library! it even explains the peculiar name subprocess. I can vouch for its quality.

Cheers for this mate. Really happy now