If your divots are left of your target after impact, then your swing is also moving to the left before impact. And I would say your club face is open to the swing path.
But as the loft increases the amount of sidespin is reduced, therefor the ball wont slice as much.
I wonder what came first...the out to in swing or the open clubface?
Bob, thanks very much for the response, food for thought as always, which prompts more Qs.... 
So in some ways the shorter irons will hide more faults so you "get away with" a less than perfect path and face relationship, which is why I think I am hitting it straight?
I also have a hunch that the leftward divots are worse on the shorter irons. Could this be because I am looking for more of a descending blow? I feel, but could be wrong, that the downward blow accentuates this leftward path, whereas a longer club, with more of a sweeping motion tends to travel straighter?
For example, my bad drive goes right, but on a straight right rather than slicing path. Is it likely I have different swingpaths with different clubs or does the forgiving nature of modern drivers mask what would have been an old fahioned slice with older clubs?
And as for this...
"I wonder what came first...the out to in swing or the open clubface?"...
do you mean I am making subconscious adjustments, maybe holding the face open to avoid a big pull? Or swinging leftward because I can sense an open club face?
Either way, I think, as per Gareth's post, the old headcover drill needs dusting off... would hat be your recommendation? It's been a while since I've trotted out onto the range to fetch the headcover I've just batted 20 yards!
