Okay, I have managed to fix this issue. Anyone who has this issue this should help.
1. Make a current backup of your flash drive (for the just in case scenario)
2. In unraid console remove the docker network database : rm /var/lib/docker/network/files/local-kv.db
3. Then restart the docker network: /etc/rc.d/rc.docker restart
After the restart br0 should now point to ipvlan. I am once again able to use a fixed ip address on br0 network for docker containers.
Thanks to bmartino1 for chimming in.
edit: you will need to re-create any custom networks and get your docker containers pointing to the relevant recreated networks. Some of my docker containers didnt restart so I had to reinstall the container with the 'newly' recreated network.
Not sure how as I tried many things, but my issue seems to be resolved. I now suspect that my problems revolved around my internet service connecting out to the Community App store, not an unraid configuration issue.
