For the light switches, it seems that a neutral wire at the switch is not required. How is the switch powered when the light is off? Do they require dummy loads?

Our switches will be direct replacements for your existing light switches and work with standard UK lighting circuits. We use novel and proprietary technology which means that our products don’t require a neutral wire in the back box. 

The Zigbee chips in the Light Switches use very little power, generated by putting a very small current through the Earth. Our products do not use a battery, do not require dummy loads, and work in the same way as standard switches. 

N.B. All installation of Den Lights Switches and Den Socket Outlets should be carried out by an Electrician.