Hi John Giles
Since the issue only affects one device on the same Microsoft account and you've already verified the normal Location settings, services, and policy-related checks, it may be worth testing whether the location platform itself is corrupted on that PC.
Try opening an elevated Command Prompt and running:
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow
Then restart and test Location again.
If the problem persists, does the Location page show any error message, or is the Location toggle missing/greyed out? A screenshot of Settings > Privacy & security > Location may help identify whether this is a UI issue, a permissions issue, or a problem with the Windows location service itself.