@AliveDevil That was very helpful, ta!
I can get some Zigbee stuff out of the Hue, but can't send the poweron state settings.
Any recommendations for a Zigbee dongle that'll work with Linux?

@Edent @AliveDevil if the lights are connected to the Hue bridge, is the power-on behaviour settings not available in the Hue app any more? IIRC it used to be.