Well that was unpleasant at this hour. Loud bang and the electricity tripped in the whole house. A heat mat for chilli seed germination has blown after 4 days of use turns out to be the root cause.
Now back to getting all my automation working again. ssh pi@192.168... oh wait, wrong window π
Yeah, thank you. Fortunately it didn't start a fire. I'm slightly concerned that I have another 4 of these running and also annoyed that Amazon wants them actually returned rather than just issuing an automatic refund.