mjkelly5a In fairness to GivEnergy, I think the problem I was experiencing was of my own making, or at least in not checking all the parameters. When attempting to keep the charge on one 5.2 Bat, in the event storm Eunice took out our power, I changed one AC 3.0 from Eco to Timed Export. It wasn't possible to do this on the beta platform so I had to change it on the legacy one.
When the storm had passed, I changed the AC 3.0 back to Mode 1 again, but then noticed while the battery was charging, it was not discharging through the inverter. When on the chat with tech support on Friday, I was informed this was still in part due to the 'plant' (more than one connected inverter) setup and without having any reliable data it's hard to know what's working and what isn't.
I tried powering down, back-up, changing the sequence of reboot etc. but nothing seemed to work. Again this morning, both batteries had charged overnight and yet only one was discharging. I was gearing-up for another chat session with tech support this morning while I was scrolling through the various options of each inverter and trying to work out what the hell was going on. Then I found it: the Operating Range slider under Battery Options. It was all the way to the right, showing reserve at 100% and usable at 0%. I hadn't changed that slider, but it stands to reason that it would be changed when moving to the timed discharge mode, or Mode 2 in old money. Interestingly, it doesn't appear that it's moved back when reverting modes to dynamic.
So, another lesson in the GivEnergy lab rat experiment. I apologise unreservedly for claiming it was a system error when it was, in fact, a user error. Proof enough that a little knowledge is a dangerous thing.