Solar during mains failure with AC coupled inverter

My interpretation of the GivEnergy wiring schematics for battery backup on mains failure with an AC coupled battery inverter, is that none of the four arrangements allow for PV (solar cell) output when on battery backup. Is this correct, and if so is there a feasible arrangement to use the PV inverter output during mains failure?

I know of a number of constraints, such as preventing the PV inverter output from feeding back into the grid during mains failure. As I understand it, for this reason my (all?) PV inverters auto shutdown if they don't see a grid voltage. So the PV inverter output would need to be switched to where it could 'see' a (pseudo) 'grid' voltage, and be isolated from the 'real' grid. That could be done by a changeover switch system that moved the PV inverter output to downstream of the battery inverter EPS output - but then the PV output wouldn't be able to charge the battery system. And something would need to be done with the PV inverter current clamp.

I am in no way an electrician, but as I understand it, one of a few issues is how to come back on to grid power safely once that comes back - as your "local house grid" would need to re-sync with the mains grid.

Yes. I think the usual solution is that, where there is a changeover switch (manual or automatic), it is of the 'break before make' variety so that the consumer fuse board is momentarily without power, to avoid the need to synchronise. I presume that, for 'normal' on-grid service, when an inverter (PV, battery or hybrid) starts up it synchronises itself to the grid, and keeps itself synchronised by watching the grid. With no grid, it presumably drifts out of synchronisation.

As I understand it, it is not possible to bring an "operating" inverter back online with the grid without it tripping out, due to "out of sync" currents.

I well remember "syncing" large rotating machines with AC supplies, and what a delicate operation it was. Get it wrong and the fault currents could destroy things!

Think this has been covered before here?