As an update.
Things are working largely as I expected - although the weather hasn't entirely cooperated.

The replaced inverter is working just fine and hasn't gone pop like the first.
I am still exporting - but today (16:27) I have generated 13.6kWh and exported 0.7kWh (5%) with the batteries at 89%. I also import a bit during the day - but its bumps on a chart and expected
According to the charts I use about 40% of my battery charge between 18:00 and when I start charging overnight so as long as I have 50% at 18:00 I am OK. I also only charge to 90% giving PV an extra 10% of headroom to fill. Thinking of dropping this to 80% and hoping for sunshine
I have also reduced my baseload by 25% which has kinda bumblebeed my calculations a bit and means I need to adjust my max SoC overnight otherwise I export more than I need to. But this is going to be hard to calculate given the variable nature of PV. If I could predict a good summers day I could seriously reduce the starting SoC
Yesterdays chart, with really crappy PV was
https://www.dropbox.com/s/ts3ocf4jyf39xp6/2019-06-20.jpg?dl=0What I need now is a good summers day to see what the chart does - see how much I export, import and how the batteries react - but I only have 20:20 hindsight I am afraid
Sean
Also - the inverter comes with a number of metrics - does anyone know what they might mean?
Qac(Var) - shows zero all day?
Vepsr(V) - I think mains voltage - hovers around 240 all day +/- 1
Feps(Hz) - mains frequency - hovers around 50
Peps(W) - a consistent zero?
Seps(Va) - also zero?
pToGrid(W) - export to grid - spends most of its time at zero, with bumps during daylight when the batteries were at or just about 100%