Birmingham clean air charge

Anybody else find it difficult to decipher where the actual clean air boundaries are? I know they say that there are 200 signs throughout the city but driving through the Birmingham area is not a good place to be looking out for those signs while trying to avoid the boy racers and other driving changing lanes and cutting you up.
I have contacted the several times but as yet have not had 1 reply.
It would be far better if the put an ANPR system in place which you can buy a tag similar to the Humber Bridge and Mersey tunnel then everybody who drives through would have peace of mind .

It’s boundary is in side the inner ring road the 4540 .

Where is the Clean Air Zone

Birmingham’s Clean Air Zone covers all the roads within the A4540 Middleway Ring Road, but not the Middleway itself

The CAZ will be in every city eventually as it’s a good money earner for the Christmas party.

While back worked for a small firm.
Lad who used drive sprinter van came.back said I think I may of gone into the London congestion zone by mistake…he wasn’t 100%sure.
So rang tfl congestion helpline. Expalined the situation.
Explained driver may have gone into the zone by accident. Can you please check find out if he did so we can pay the charge.
Was told lot of stuff about data protection we can’t say who has hasn’t emeterd the zone.
Said I’m happy email copy of log book any details as proof of ownership of veichel etc.
The refused.
I asked well how do I know he entered and if I have to pay.
There response was you don’t.
You take you chance don’t pay them you could get a fine or a summons though the post.
End day just payed the charge and have no idea if he went in there or not.