The most common luggage rack seems to be the 'with side-screen storage' version. It locates onto over-rider brackets with cranked L brackets and a nut & bolt each side. It locates onto the full rear bumper with similar but flat brackets. The T bar fixing is a flattened part of a cross tube which is exactly in line with the spare wheel centre.
I have what sounds like this version, bolted into full width bumpers, but without the side screen storage.
Not sure if you already have this one in your image library Dave.