Manjaro xfce4 2 x GT710 and 4 monitors (only 1 GPU working)

I’m using 2 x NVIDIA GT 710 cards with four monitors cabled up in the following way:

Card 0: GT 710 — 1 x DVI and 1 x USB
Card 1: GT 710 — 1 x DVI and 1 x USB

In both the xfce Display application and the NVIDIA-settings GUI, only one GPU and attached monitors is enabled and I cannot enable or use the other GPU and it’s monitors.

I had a working config from when I was running Ubuntu 20.04 that i saved but since moving to Manjaro that config doesn’t work - see attached file.
xorg.conf (2.9 KB)

Can anyone help me to get this working in Manjaro?

Thanks in advance.