Video:
The Brent (Prescribed Routes) (Pedestrian & Cycle Zone) (No. 24) Traffic Order 2022.
The ambiguous wording about the payment deadline is one arguable point, and the red advance warning sign is illegal (contrary to popular belief, advance warning signs are prescribed by the TSRGD). Is that sign still there, can you check and get a photo?
Also, according to the traffic order:
"prescribed street" means that length of Slough Lane, between a point opposite the party wall of Nos. 93 and 95 Slough Lane and a point 12.00 metres north-east of a point opposite the common-boundary of Nos. 144 and 148 Slough Lane, and the entire length of Woodland Close;
I'm not convinced the sign is positioned where it's meant to be:

It should be right across
this drive.
Could you go back and measure the distance
from the boundary of the two properties on the right, and the pole on the left?. If using a tape measure make sure to keep it parallel to the kerb.