Hello samanfromrutherford,
Thank you for reaching out in Apple Support Communities. Per this support article Set up HomeKit Secure Video on all your devices - Apple Support it states the following:
If you have devices where you’re not signed in with your Apple ID or that have the Home feature turned off, you won’t be able to view or share HomeKit Secure Video on those devices.
You'll want to make sure that the Home feature is turned on in order to view the recordings.
If you need further assistance, you can contact Apple Support through this link here: Apple - Get Support
Kind regards.