I probably can get the container way working now I've had some time with it. The problem is routing it through Mullvad. Prowlarr deffo needs to go through it, otherwise it can't see the indexers (I've been using Prowlarr without a VPN for a while and it's much better with it). Debrid doesn't need a VPN I just prefer it to be there
I watched a YouTube tutorial to get an OpenWRT container set up to route traffic through ,and managed to get it working. I struggled however to set the VPN up through it, I feel like I was in spitting distance!
The bonus of using that method was that I could have multiple containers use the OpenWRT container, meaning they would all share the same IP address and just have different ports, so all my Self Hosted containers would be in the same place on my network.
I'll keep plugging away and give pfsense a look. Now that I have OMV running I can kill my Windows server without losing the media