Interesting. But that article is talking about idling while stationary - not about leaving the car running while you're not even in it.
And even then it contains this sentence:
"In England and Scotland, leaving your engine on while parked on the road or in a public place could land you with a fine."
I'm not saying you're wrong - I'm genuinely not sure myself - but I don't think that article really proves it one way or another.