Literally just found it as I was reading this...the unit was sitting on a solid Red lamp.. Seems if its on already and you power on the device you have to reset the 'virtual' switch to make it do stuff. Or perhaps a software anomaly.
Annoyingly the OS X instance of the IOS app isnt great...seems to do kinda whatever it wants but the native IOS app does work...almost no pwr from the grid now and everything seems good. Unit is floating around the 29.5 deg C mark with 2x295w supplying the PV.
So far so good, took a few on and off's but seems to be good now...
edit: Temp of the unit has crept up to 32.1 Degs C - Interestingly the 'Power_Adj' feature doesnt seem to make a blind bit of difference.
edit1: Grid power use starting to increase as PV drops, also didnt see any temps go above 34.5DegC, I suspect if you were pumping the full 1200w's in.out of this devices you would most certainly need active cooling. The most I had was around the 350w mark and saw temps approaching 35DegC. If the conversion rates on the device are to believed then the efficiency is in the low 90%'s which is pretty good I guess.