Hi, Thanks I have seen that manual however it doesn't match my inverter settings unfortunately.
On my inverter setting [02] reads SNU 60, which I'm guessing means solar and utility charging, max 60A.
Setting [01] reads UPS, with other options for this setting being FL and PO. I have no idea what FL or PO are, so I have left this on UPS.
As far as input voltage ranges go, setting [05] has options Fst, APL and sLo, which seem to correspond to entries in a data sheet posted earlier in this thread which reference switching speeds and voltage ranges. I've tried all of them with no change. I think the generator outputs a pretty stable 240V and the problem maybe lies with high frequency harmonics causing the inverter to reject the input.
I've been tempted to get a new inverter just so I can have a manual!