Seems if my battery SOC is below 100%, my inverter will show higher peaks of generation.
Until today, the highest peak I'd seen was just over 5.4kW, but this morning, while the battery was being charged from the panels, I briefly saw 6.451kW
I'm tempted to try turning off charging overnight completely.
At the moment I have it set to 80% and overnight it was still 80% at 2:30am and just maintained the level until 5am (octopus flux), using about 1.1kW from the grid.
{edit} I've lowered it, but left it at 66%, just in case.