I agree with you. As the thread starter my main complaint was the poor signage, which unlike the congestion zone is not that clear. On another point like you I thought, incorrectly a modern diesel engine I expected to be compliant, my 8 year old car isn't. My daughter's Focus which is 16 years...
Didn't say I'm against it but having clear signage like the congestion charge area would be a benefit. The lack of signage has nothing to do with saving lives it's purely to fine people.
So not only was it the most pissed off I've been for years at the Spurs game, today I got fine through the post for entering the ULEZ money making area.
Straight off the North Circular you're in the zone so I found out. Here's the tiny sign you are supposed to see when coming off the roundabout...