Watch face support for Vivoactive 3

I have downloaded the latest 2.3.4 SDK and included support in my watch face for the new Vivoactive 3. Everything seems to test fine in the simulator however I have users reporting fundamental things do not work. When notifications arrive the screen blanks out and just displays the Garmin 'blue triangle'. If they long press on the face the options appear but when the select watch faces and scroll to my watch face nothing appear.

There is nothing in the CIQ_LOG.TXT file so it seems like there is something I am not returning from the onUpdate or onLayout functions that is expected on this device ? or some new function call for single button devices I am not supporting ? I have read what I think is the available documentation on supporting Vivoactive 3 and cannot find anything. Can anyone point me at some other doco, topics or samples in this area ?
Thanks