I have OpenVPN working on my ER605 and it is successfully setup so I can access it remotely and it will forward my remote connection via my ISP. I've set it up this way as I like to occasionally work out and about but in order to access work servers, it has to come from my authorised static IP.

However. The way it is setup at the moment, I am bombarded by adverts as it is not using my AdguardHome setup on my Pi's that I would normally use if connected to my home network.

See setup below:

As the IP pool is different to what my LAN issues - 192.168.0.5 for my AdguardHome DNS server - can I simply put this is the primary DNS server? I'm reluctant to mess with the settings as it has taken AGES to get it working to the current level.