Home Network - Traffic from Mesh not being routed via VPN

Hello!

I have an ISP router (192.168.1.1) that I have plugged in to a mini-PC (I will call this Firewall) that has 2 physical ethernet ports:

Port 1 - 192.168.1.5 (connected to the ISP router), known as Ethernet in the attached

Port 2 - 192.168.50.5 (connected to my home mesh network), known as Internal Network in the attached

This bridge PC (Firewall) also has a VPN on it and connects correctly to the xxxVPN static IP address I have.

The bridge functionality works and routes all my .50 traffic, regardless of VPN being turned on or off, through the "normal" non-VPN route via my local ISP rather than the VPN tunnel.

The aim here is to have all traffic on my .50 network routed through the VPN connection, however, this isn't working for traffic on the .50 network, only the local apps on Firewall PC.

I have also tried bridging between Internal Network and xxxx OUTBOUND Connection but, this doesn't work at all.

Just to be super clear, the BRIDGE functionality of Windows is working perfectly in that the .50's can access the internet (non-vpn route).

Any thoughts on how I get ALL traffic, including the .50 devices to go through the xxxx tunnel on Firewall PC, please?

(Exceuse the blank spaces in the diagram, when posting I discovered I should not use the VPN supplier name so, quickly redacted these)

Edit: sorry, should have said that the firewall/bridge PC is windows 11 and running the VPN own client due to their excellent but proprietary protocol (xxxxLynx)

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