Support for second. legacy GPU

Running Ubuntu (Studio) 20.04

Main main card is GTX1060 and I’m running proprietary NVIDIA driver 440.
I have a Quadro FX1800 installed and want to run a second monitor on this to set up loginctl-based multi seat.
There is no output to the second monitor but the card is recognised / reported by lspci and lshw (which shows it as UNCLAIMED) , but not by loginctl

lspci | grep VGA

03:00.0 VGA compatible controller: NVIDIA Corporation GP106 [GeForce GTX 1060 6GB] (rev a1)
0b:00.0 VGA compatible controller: NVIDIA Corporation G94GL [Quadro FX 1800] (rev a1)
sudo lshw -C display

  *-display                 
       description: VGA compatible controller
       product: GP106 [GeForce GTX 1060 6GB]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
       configuration: driver=nvidia latency=0
       resources: irq:43 memory:f6000000-f6ffffff memory:c0000000-cfffffff memory:d0000000-d1ffffff ioport:e000(size=128) memory:c0000-dffff
  *-display UNCLAIMED
       description: VGA compatible controller
       product: G94GL [Quadro FX 1800]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:0b:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller cap_list
       configuration: latency=0
       resources: memory:f4000000-f4ffffff memory:e0000000-efffffff memory:f2000000-f3ffffff ioport:d000(size=128) memory:f5000000-f507ffff

nvidia-settings UI does not show or detect the second display / card in X server settings

I found this in nvidia-bug-report.log which I assume is relevant:

NVRM: The NVIDIA Quadro FX 1800 GPU installed in this system is
                                  NVRM:  supported through the NVIDIA 340.xx Legacy drivers. Please
                                  NVRM:  visit http://www.nvidia.com/object/unix.html for more
                                  NVRM:  information.  The 440.100 NVIDIA driver will ignore
                                  NVRM:  this GPU.

The only available option for this card in Software & Updates | Additional Drivers is “Continue using a manually installed driver”

What do I need to do to be able to run both cards & monitors please?

(Compressed .gz log attached with .gz extension removed)nvidia-bug-report.log (299.7 KB)