CUDA errors: non-NVIDIA GPU is running as primary display + windows 43

I’ve read everything I can find on the 2 errors below and not solved it for me. On a desktop machine that worked fine for ages, hadn’t used CUDA for a while and now won’t get going. The below error makes me think that NVIDIA know there’s an issue in this setup (now?). How do I get it (back) to a working state?

nvidia-smi dmon -d 5
NVIDIA-SMI has failed because it couldn’t communicate with the NVIDIA driver. Make sure that the latest NVIDIA driver is installed and running. This can also be happening if non-NVIDIA GPU is running as primary display, and NVIDIA GPU is in WDDM mode.

  • Radeon HD 7000 GPU for monitors (i.e. non-NVIDIA primary)
  • Geforce 1050 ti for compute (Can only do WDDM, not TCC)
  • I've an uptodate Windows 10 and BIOS
  • I've completely cleaned and updated Nvidia drivers and toolkit (CUDA 9.0)
  • Does the above error lead to Windows 43 in device manager?
    Windows has stopped this device because it has reported problems. (Code 43)
    There’s loads of threads on this, very few on the above. I’m not sure which ‘comes first’? i.e. Windows stops driver, so above is “not running”, or driver reports an error to windows which calls it 43

    Thanks in advance for any and all help