Rob.. Interested about the adjustments being done while you wait.. I've asked this on the Canon forum with no result - why can't one "calibrate" one's camera oneself? I'm a Radio Amateur and have spent my life setting up my own radio gear and plenty of other domestic stuff too. What's involved in the "calibration"? If it's simply taking a panel off and twiddling a screw I'd prefer to do it myself.
I've checked my EOS20 and my 17-40 and 24-105 "L" lenses with a focus chart and everything focuses "in the middle" so I'm not sure it's a focus problem. I'm not a professional, far from it, but do understand the basics of DoF, shutter speed, f numbers, etc., having used SLR cameras for 40+ years.