The bumper is attached to the shell with six bolts which were very simple to remove. The indicators have captive bolts which sheared off when I attempted to loosen the nuts. Use of heat was not an option because of the rubber bush and plastic lens. On reflection I should have tried a bolt splitter (or soaked longer with oil). The headlights are attached with a single screw at the bottom of the unit. Once removed the headlight simply unclips from the wing. Here is a picture of one of the headlight units dangling:
The unit is free once the spade connectors and the black socket have been unhooked. Initially I was puzzled by the fact that the black socket is too large to fit through the hole in the wing. However the connectors can be removed from the socket by depressing the small lugs (if that's the correct term) with a small screwdriver. Once this has been done the wires fit through quite easily. It's a good idea to immediately reassemble the socket immediately.
In the run up to this job I had soaked the wing bolts in penetrating oil from inside the boot. This meant that the majority of the bolts undid quite easily. The exception being the bolt at the bottom of the A-post. On both sides the captive nut immediately started to spin. I'll need to think about how best to fix this (the drivers side should be fine as I need to patch the bottom of the A-post anyway). Here is a photograph showing what I was left with (notice that the extent of the historical repair to the shell is quite clear in this photo):
