I don't suppose anyone knows about Emailair "Hi Wall" split air conditioners?

I have a S18HA/C18HA that was working just fine upstairs. The air con guys installed a ducted system, and relocated the old emailair unit to the study. Sounds straightforward, right? Wrong...

It won't switch on. The sparky swears the wiring is right, but it just seems to be hitting a cutout (there's a relay click when you turn it on, and then it clicks off again). The "Operate" LED just flashes slowly.

If I put it onto "Auto Louvre", the louvre motor cuts in & out in the same sequence.

Not happy right now...