Here are a few photos of the arse end of a light unit. I'm guessing the hatch for the Angel Eye light units is the oval-ish one at the bottom.
If you look in the 2nd and 3rd photos and look past the main reflector towards the 'front' of the light unit, it looks like you can see the base of the AE units (the white 'L' shaped item). In the 3rd photo there seems to be wires inside the block that the oval port covers.
Has anyone removed this cover and peered inside?