Meanwhile the 3rd party integration that David created continues to work nicely!
The only problem with it (and from what I remember of the beta 'official' integration) is that it only exposes the individual zones - there's no concept of the system as a whole. So if, for example, you sat one zone to 'away' mode it actually sets Evohome to away mode, affecting all zones. Ideally the system/controller should be exposed at the thing that you apply heating modes to. Much like how Domoticz does it.