To view or control your home's Home/Away state from Apple Home, enable the Show Home Occupied switch (Home/Away control) option in the Starling app, under Home and Device Settings.
If you enable this option but have not set up presence sensing in the Google Home app, the Home Occupied switch in Apple Home will not be available and you will see the following warning in the Starling app under Help and Troubleshooting:
To set up presence sensing, go to the Google Home app, Favorites tab, then tap the down arrow next to your Home's name in the top left of the screen. Then, press the Set up presence sensing button and follow the in-app instructions. The warning will then disappear from the Starling app and the Home Occupied switch in Apple Home will become available.
Some customers have reported decreased battery life on their iPhone when using Google Home's presence sensing, so if you previously used the Nest app for presence sensing and wish to continue doing so, having completed the above step, you can return to the Nest app and re-enable Home/Away Assist. This will automatically turn off presence sensing in Google Home so only the Nest app is used to control Home/Away state. After re-enabling Home/Away Assist in the Nest app, you can continue to use Starling Home Hub's Home Occupied switch in Apple Home.