Well, it's back, and with only a really quick couple of tests it seems to be much better.
I have a hand held low light shot of a focus chart that isn't worth posting here, but does show a big improvement.
The only other photo I have to demonstrate the apparent improvement is this shot taken yesterday in really difficult conditions.
This lizard ran up to a pool, took a drink, then ran off to a gap in a fence in a tight little corner.
With wet hands I didn't change settings so it was badly overexposed and took a lot of saving in PP.
Auto focus point says it was on the top left corner of the eye, and that's near enough to where I had it aimed at the time I took the shot (I'd aimed for the eye), but to me the neck seems to be more in focus, but at this crop level, that would only be out by mm's from where the red square is, and is at least at approximately the same depth as the point I'd aimed the red dot.
I'll post some proper focus chart images soon, but so far I'm much happier with it.
Yarrangobilly Jan 2012_023a.jpg