Well, I cloned the old network it was previously attached to , and could get to the printers web page. Lovely! I could see all of the ink levels and stuff and all of the network settings. Cracked it!
No. The web page does not offer any method for changing the network settings.
Finally cracked it though. I built a virtual Win11 machine, and amongst various bits of software I found one called EpsonNet Config. Installed and ran this and there it was. Network settings that you could change and transmit back to the printer.
Oh, and I added extra garlic, which I think what was finally fixed it.