Hi robfreeman,
The following guidance can help resolve issues with HomeKit accessories:
"If accessories from one manufacturer aren't responding
Check if your smart home accessories are responding in the Home app after each step.
- Turn on Bluetooth in the Settings app on your iPhone or iPad, or in System Settings on your Mac.
- Restart any accessories that aren't responding. You may have to take the batteries out of your accessory and put them back in.
- Check the manufacturer's app to see if accessories that aren't responding in the Home app need a firmware update. If the accessories aren't responding in the manufacturer's app, you may need to reset them.
- Restart any third-party bridges and all home hubs (HomePod, HomePod mini, and Apple TV) by unplugging then plugging them back into power.
- Remove accessories that aren't responding from the Home app. Select an accessory, scroll down to accessory settings, and select Remove Accessory. If you don't see the option to remove the accessory in the Home app, it must be removed through the manufacturer's app. After you remove the accessories, follow the manufacturer's instructions to reset them and add them to the Home app again.
If your accessories still aren't responding, contact the manufacturer for support.
If accessories from several manufacturers aren't responding
Check if your smart home accessories are responding in the Home app after each step.
- Update your iPhone, iPad, or Mac to the latest software.
- Close the Home app on your iPhone, iPad, or Mac and reopen it.
- Make sure your iPhone, iPad, or Mac is connected to the same Wi-Fi network as your accessories. To control your accessories remotely, you must set up a home hub.
- Turn on Bluetooth in the Settings app on your iPhone or iPad, or in System Settings on your Mac.
- Restart any accessories that aren't responding. You may have to take the batteries out of your accessory and put them back in.
- Check the manufacturer's app to see if accessories that aren't responding in the Home app need a firmware update. If the accessories aren't responding in the manufacturer's app, you may need to reset them.
- If your accessories still aren't responding in the Home app, restart your devices:
- Unplug your modem and router, then plug them back into power.
- Unplug any third-party bridges and all home hubs (HomePod, HomePod mini, and Apple TV), then plug them back into power.
- Restart accessories that aren't responding. You may have to take the batteries out of your accessory and put them back in.
- Restart your iPhone, iPad, or Mac.
- Check VPN and third-party security software to resolve potential network connectivity issues.
If your accessories still aren't responding, contact Apple Support."
Cheers.