Trouble Starting PiHole

Hi folks

Have moved this to 3rd Party Integrations as I had it in configuration with no responses.

Looking for some advice as I seem to be going round in circles.
Background
Hassio running in a container on Ubuntu 18.04 1 LTS Desktop

About a week ago I noticed that Pihole had stopped blocking adverts so thought I would look into it.
First issue came when I tried to remove the add on last night and then re add it -Kept getting the red button (and the same on all add ons ). Anyway it transpired after some troubleshooting that DNS had stopped working on the desktop.

I have been playing around since and I am getting in a mess (not a Linux expert :))

In order to get DNS working again I found some advice to add dns=dnsmasq in the NetworkManager.conf in etc/NetworkManager

I was then able to access the web and did a Sudo apt-get update and upgrade thinking that would resolve things.

I was then able to start the install of PiHole but it always ends in the logs with “dnsmasq: failed to create listening socket for port 53: Address in use” and then the webUi just shows its lost connecttion to the api.

Since then I have installed dnsmasq (and then uninstalled it), I have looked at the pids in netstat -tupln and then killed the pids that were on port 53 (all said dnsmasq and all reappeared when I re-ran netstat again).

I am getting a bit confused as some advice suggests editing resolv.conf (mine has 3 entries for nameserver - 19.2168.1.117 (the problem Ubuntu machines, 8.8.8.8, and also the default gateway (router ip address).

I have also followed other advice to uncomment the DNSStublistener=no line in the etc/systemd/resolved.conf file.

Any ideas and thanks in advance.