I totally forgot that if you use the console you forgo any achievements for that gaming session. So when I had to 'release myself' from the side of the wall using the no clip code while at the end of the Thieves Guild questline (where the water rises in the room....?) I think I've missed out on my achievement for finishing the line. I take it I'd have to do it all again on another character? Or will I automatically get it when I log back into that game?

I think it's only for that session. So if you log back in, and go back to a save just before the end of the quest, you should get it.

Lovely - thanks.

Using the console has no effect on getting Steam achievements what so ever. I was testing a crafting mod I was making and needed to give my test character a bunch of gold in order to try some things out, I mis-typed and ended up giving myself 100,000 instead of 10,000 and promptly got the achievement for having 100K gold at one time (whatever it's called). I didn't care as the whole achievement thing is completely pointless and meaningless to me, but it was surprising that it happened all the same.

Bear in mind that you also must be connected to Steam to receive achievements; you may not receive them in offline mode.