Hi there, Beefyhill-1.
Sorry for my late response. Thank you for all of your patience while waiting for a reply. I just wanted to make sure that your issue is addressed. Yes, you would need to have two subscriptions for two separate Home/structures. One Nest Aware subscription per home/structure is how it works. If you own multiple homes with Nest/Google products in them, you would need a separate subscription for each home.
It looks like we haven't heard back from the OP so I'm going to go ahead and lock the thread. If you have any further questions or concerns, feel free to create a new thread.
Have a great day,