I believe the fog lamp mountings are plastic lugs welded to the rear surface. I guess we'll will have to use a resin of some kind to fabricate reliable mounting lugs. Perhaps a fibreglass type of thing. The grills have a rather poor mounting system from what I've read. That will be a matter of seeing what the grill has in the way of attachment points and fabricating something on the rear of the bumper to take them. The indicator lamps just clip into the cutouts in the bumper. The screws, fir tree coupler gizmos and other bits and pieces are probably available from Rimmer/Xpart if necessary.
See this:
http://www.rimmerbros.co.uk/Item--i-GRID001779
And this:
http://www.rimmerbros.co.uk/Item--i-GRID001777
TC