There’s no first time offence thing.
I did similar Essex way Romford I think.
Either way bus lane was only maybe hundred yards long I drove into it not realising
To be honest was to busy looking at unit names and numbers didnt expect to see a bus lane near an industrial estate.
End day just one of them things.
Links you post basically mean the following to keep it simple.
If a council decides to install a new camera or. Change a speed limit put in a cycle lane etc
They can’t issue tickets until the new camera /limit has been active for 6 months . It gives drivers time to get use to the new changes .
Once 6 months have passed they can then start to issues tickets from that day onwards they can’t backdate it to when the camera was installed.
If you get caught by a new camera/ speed limit them can send you a letter saying be aware
but they can’t fine you unless the offense happened 6 months after the day the camera was 1st installed
Hope that makes sense.