Today i replaced the bulb that had blown behind the digital clock on the back of the dash. I noticed that a couple of the instrument warning bulbs were missing one was for glow plugs which i havent got as its a 16v gti. The other was for brake disc wear when i put a bulb in it doesent go off with the rest of the warning lights. Did all gtis have brake disc wear light as standard or as the owners manual states it was optional, i have only just got car and am wondering if previous owner had removed it or it simply was never there any help appreciated.The brakes by the way seem fine