Thanks Dan
I have seen recommendations to remove dhcpcd5 so I have. Source: Ubuntu network broken after Pi-hole uninstall - SOLVED - #3 by deHakkelaar
I'm down a bit of a rabbit hole here. Quite interested to try and rectify without LAN (means moving Pi, monitor, keyboard, mouse up to the router where ethernet is available) or flashing (kinda boring and we don't learn anything.
This issue is quite unlike any other I have read. I particuarly cannot fathom why raspi-config is no longer available. Surely that is not a prerequisite?
Any tips on what should be in /etc/dhcpcd.conf?