Electrically, it's all good. Hence my question around temperature. I'm using it as remote ignition switch but the switching is done by a separate relay. This only controls the relay coil so current draw is very low. Initially I had a cheap eBay unit which worked for a couple of weeks. This one lasted one weekend.
The strange thing is that it works at the end of a ride, switches the bike off. Next day, nothing. I'm gonna look at trying to monitor the airbox temp after I switch it off to see if there is a temperature soak after the bike is switched off in a confined space (garage).