Hi James,
Thanks for the positive comments. Yes there are some light switches, but my intention is that in time they won't get used as the system gets better. At present the lights (and heating and other stuff) is controllable 3 ways, the main way being automatic, i.e the lights come on when it's dark and when you are in a certain area, secondly you can use a smart phone or tablet/laptop to operate anything directly via a web interface, and finally you can use a switch which act as a digital input indirectly into the raspberry pi's, which can override the other 2.
The DMX has been rock solid. I've had some of the dimmers for 8 years or so, they've never let me down.
Some manual intervention, but that's just software, generally the system is reliable, I just write poor/rushed code at times!
I've no idea if the dimmers waste power when off, I suspect there is an element of that, but it can't be much, they are always cool to the touch.
Cheers
Dan