Just to add my two-penneth worth to this thread. I went into Tony Purslow Guildford today to get the AGW upgrade done and to pick up the new head-unit upgrade CD that I ordered on Monday (£7.72 incl VAT - a new low I think?!). They also insisted on doing a couple of other service upgrades that were showing as outstanding, including an update to the gearbox software that required taking the car to 80mph and then allowing it to slow to a complete stop without touching the brakes to recalibrate it. (Anyone heard of this before?). While I was there I also took advantage of mercedes new offer on the web-site of a £20 pre-holiday check which included a free continental driving kit of GB stickers, headlight deflectors and a fluorescent jacket (which apparently is now a legal requirement in most countries including France just like a warning triangle and bulb set). For once I was delighted with the Purslow service which included a wash and valet.
While loading the head-unit software (which took over 10 minutes) I was a little concerned when, after it was 50% completed, a warning message came up that it "CAN-T READ" the nav DVD player in the boot. But after hanging for a minute or so, the software update just switched on to the fourth and final part of the upload and then completed successfully before ejecting the disc. Everything seems to work eg. ETA permanently on main display - does anyone know if the missing section is unusual or important?
One final moment of panic when I found I couldn't turn off ""Veronica's" voice in the usual way by pushing and holding the mute button while she was talking (love her though I do). Eventually discovered that one of the more subtle changes in this version is that you have to just touch the mute button briefly to achieve this now.
All in all, a good day with Mercedes I reckon