Have a slight oil leak at the bottom left hand side of the engine (when looking at the engine from the front). It seems to be just above the air conditioning compressor, not much on the head, mostly on the block. Anyone got any ideas what it is?
Photos:
http://www.facebook.com/album.php?aid=112809&l=78e8a&id=739570231

That's no S54. :stickoutt Looks like you might need to replace your valve cover gasket. Pretty cheap fix if that is indeed the problem.

I'm not sure if its coming from the valve cover or the head gasket. I've wiped around the area and will drive it around a bit more and see if I can track it.

What I'm wondering is, is I thought that if it was a headgasket, there would be anti-freeze in the oil and oil in the anti-freeze but I don't see any signs of that. Or is it possible to have a leak from the headgasket (between the head and the block) without having the oil and anti-freeze mixing around?

I can't tell from the pictures, but my guess is it's your valve cover gasket. If you had a head gasket leaking oil, it would probably be leaking other stuff too.

On the last picture, one of the the bolts that goes into the block from the front of the car is missing. You can't see it in the picture, because it is hidden behind a belt, but could that potentially cause a small leak between the block and the head?

To me it seems to be coming from the headgasket but the oil and antifreeze aren't mixing and it has never overheated so I'm a bit stumped.

Ok, it's definantly coming from the headgasket, but the oil and anti-freeze are not mixing...Is this possible?

Yes, A head gasket can leak externally only. It can, however, become worse and leak internally, mixing with the coolant. If the car is blowing thick, white smoke after start-up, then coolant is leaking internally, blue=oil.

Updated photo pics http://www.facebook.com/album.php?aid=112809&l=34ebd&id=739570231

I'm pretty sure its the headgasket. Is this a common problem on the M43 engine?

I didn't know E46s had those... nice. I had one in my 1991 E30 318i (a M42). We don't have M43s here...

Anyway, just wanted to comment on that... sorry I can't help beyond that, especially being that we don't have M43s in the States. For M42/M44s, I don't think HG leaks are especially common, but obviously they can happen, especially on higher-mileage or overheated cars. Your car may have been overheated before you owned it--or even while you owned it.