Thought I would share this piston as something I have been trying to get working for ages, webCoRE and the Beta Presence sensor helped get me there. Also a bit of searching on here helped me find the correct command to use.
So with that in mind, the piston is actually very simple but allows for the Nest thermostat to be in Eco whilst away and start heating when returning. However, it keeps Nest in Away mode so the Nest camera’s stay on whilst you are traveling home.