If i remember rightly first remove the inspection panel at the corner of the spoiler , there's about four or five screws holding it on , then you'll see underneath the lamp one screw in the middle , that's the only one holding the bottom .
It's not really a screw in the true sense of the word , it only turns about half a turn and it's undone , you'll find there's two on the top exactly the same , they're a bit of a fiddle to get a driver on and it's probably easier to take out the side indicator lamp for access to the heads of the screws ,
assembly is the reverse as they say
Derek..