My mistake, it has got pad wear indicators, inside front pads only. There's plenty of life left in the pads but I had an annoying warning light on. If anyone else has this problem unplug the pad indicator, bridge out the 2 wires in the plug with a split pin/paperclip or whatever you want, tape up the plug to stop water getting in and this will stop your light coming on. Obviously you have to keep a visual check on your brake pads. Your brake controln unit sends out a low voltage signal to your brake pads and needs to get a low voltage signal back to say everything's ok. If for any reason the signal is interrupted or goes to earth, it will bring your light on.