It has been a couple of years since I asked this question and Garmin still haven’t answered it to my satisfaction. All that has happened is that the original question is now locked.
Garmin Express was slowly updating my brand new Etrex 22x micro SD card, then with 2 hours 24 minutes to go it suddenly slowed from 3.4 mb/s to 406 kb/s. It has since crept up to 507.7 kb/s and still has 5 hours 2 minutes to go.
Garmin please accept that Express is faulty and do something about it, continuing to fob us off with excuses is an abuse of your monopoly!
Still frustrated,
Steve