Upon several hours investigation with Google support, it turns out the
issue is a server issue on the side of Google. Tech support unable to
fix, the issue was classed as unsolvable and I was advised to live with
it.
To make matters worse, the thermostat happily connect's bto an
alternative google account I own (that isn't upgraded to a Google Home
account). All arrows point towards the nest thermostat NOT being
compatible with Google Home (despite what the liter...