My nearside front foglight bulb has blown and I'm trying to replace it.

I've got the bulb spec, but am struggling to actually figure out how to get into the unit to replace it. The owner's manual is curiously silent on the matter, and the workshop manual I have is for the US, where of course they don't have fog (or something).

I had a bit of a poke around the front of the car at the weekend - there are a couple of screws that don't seem to do much, and a rusty-looking bolt that I can't seem to shift.

Does that rusty bolt hold the whole unit in and the bulb get replaced from behind? Do I just need a torrent of WD40 and a bigger breaker bar?