Problems unlocking Mac with Apple Watch

Hi everyone.

I know this topic has been covered elsewhere but I am still having problems unlocking my mac with my watch despite trying all the fixes I have found. I get the message Your Mac was unable to communicate with your Apple Watch, despite my phone being unlocked and the unlocked watch on my wrist and unlocked.

This has happened before and I have been able to get it working by deleting the plist files etc. Not this time.

It's a pity that this super useful feature is so troublesome, for me at least. Does anyone have any further ideas beyond the bluetooth on/off, restart (duh) and plist solution?

Cheers,

Mark