I have a similar light and above the PIR there's a flap that lifts up, revealing some adjustment knobs.
Thanks for that info ATJ, didn’t know there was any adjustment knobs and nothing is mentioned in the instruction leaflet. The replacement is due either tomorrow or Monday so I’ll check that when I take it down when swapping over to the new one.
Just to say thanks to everyone who contributed to the post as I got it sorted yesterday. Replacement working well (not sure now whether original was defective) however no mention in the instructions about the adjustment screws and being a non spark didn’t realise they were on the unit, I might email the supplier to mention this. Again working well, however one last question should anyone know…… There were 3 adjustment screws, left side for the time duration, one on the right for the light (Lux) but what is the middle adjustment screw for?