"PKCS#7: Signature not signed with a trusted key"

We’re trying to install cuda-10-0 on Ubuntu 16.04 Desktop edition using the .deb file install and the repo: cuda-10-0, something we’ve done quite a few times before without a problem.

We are on the GTX 1060 on the nuvo-7160GC-PoE

After installing as described above and rebooting, we get no output at all from the GPU.

If we connect to the IG, we get no GUI desktop and see what appears to be an fsck and the repeated error message running down the screen of:

PKCS#7: Signature not signed with a trusted key
bbswitch: no suitable _DSM call found.

We have tried purging cuda*/nvidia* and reinstalling a couple of times with no obvious errors

We are running the same cuda version and kernel version (default) as on multiple other machines and secureboot is disabled.

The output of sudo apt install cuda-10-0 is https://pastebin.com/MVP4F2KX - no obvious errors in the module build.

Please could somebody help me diagnose (or even solve!) this problem?