All in One 3.6 - can I upgrade the inverter

I had an AIO installed two weeks ago after asking three installers to quote for the cost of installation. Stupidly didn't check every question with every installer. So it was only after the unit was installed that I realised the cheapest bidder was the one I hadn't asked about the maximum output of the battery. So I have an AIO 3.6 rather than the 6 I had planned for. Maybe not such a bad outcome because I have max 5kW output from panels and a max export allowance of 7.5kW. But galling all the same that the installer did not mention there were more than one model of AIO. I'm also feeling annoyed I had missed this.
Anyway, assuming I can get the DNO permission for a higher max output to the grid, does anyone know what the logistics and costs are for (presumably) replacing the 3.6kW inverter for a 6kW one please?

And finally I have noticed that the maximum draw I can get for the house is 3.6kW.

The GE sites states "3.6kW peak power on-grid, 6.0kW off-grid". If this means 3.6kW is all I can get this is really irritating as I have a 5kW air source heat pump! Does the GE statement mean I would have to disconnect from the grid to get 6kW?

Here are my battery settings:

Thank you very much for your advice. I'm a newbie at this and I suspect, like Microsoft Windows, I would need to get to version 3 before I have a system that works the way I want - but hopefully with your collective knowledge version 2 will do the job!

So in theory if you force off grid the you should be able to pull 6kW.
However that does mean if you pull more than that, the system will shutdown so not that practical for a house.
The fact that it can do 6kW off grid tells you that the AIO itself is no different physically, and the 3.6kW part is just a software limit.

I read somewhere (that I can no longer find) that the switch from 6kW to 3.6kW is a one time only thing and you can't go back again. How true this really is, I don't know (it may be such at say installer level, but Givenergy have 'God mode' access) if you speak to GE, you may be able to get them to force it back up to 6kW if you get the right documents from your DNO.

hoggy thanks very much I'll see what GE say.