Street lights have been present in the industrial estate, but even signage near entrance on main road always indicated 40 for the entire area.

but no 40 repeater signs in the actual area that changed...which begs the question, and I did ask them and never got an answer

How far after a 40 sign does the speed limit change to 30 if there isnt a further 40 sign if the entire area has lighting ?

I did record dashcam video and maps photos etc from the time of the entrance etc, but deleted it recently, as this incident was about 2-3 years ago.