Reinstalling Docker image keeps pulling config from somewhere

And I have no idea where.
Trying for the life of me to reinstall NextCloud-Aio-MasterContainer. Every time I fire it up it's asking me to log in, like it's done its initial startup already.

There is no folder in appdata, even when installed, it's not there.

I deleted the "Add Container" xml file.

I also ran find / -name *nextcloud* from /mnt/user and deleted a whole bunch of files. One of which was in /var/lib/docker/volumes - which upon reinstalling wouldn't start the docker image as it was missing this folder, so had to create it manually.

I've ran a Docker Scrub

I've ran a community script: docker rmi $(docker images --quiet --filter "dangling=true")

Any ideas how I can shed this docker and its config in full so I can reinstall? 

Thank you