..also, the only other thing that wasn't plain-sailing was bluetooth sync (iPhone) of the completed activities - basically it seemed to need an unknown number of attempts and Garmin Connect force-close/re-open/sync request before this happened. But it did in the end for Stages 1 and 2, and then 4, before Stage 3 finally sync'd on the train on the way home. However bear in mind we are talking locations with poor data connectivity, my phone running in power save mode (which I've found Garmin Connect sometimes doesn't like) and of course unusually big activity files. Like I say it worked eventually.
Basically this is one area which doesn't seem to have improved at all from previous units. Previously I've found via either Bluetooth or, back at home, Wi-Fi, things will sync eventually, yet out-in-the-field it's not something you can rely on.. especially not if time-pressured.