I just installed it through Aurora Store, and it works. It installs fine, but it can’t quite get through the signup process, not responding when pressing ‘Create account’ at the ‘Optional contact information’ step. Once you hit that wall, you can just press back a couple of times and then sign in with the email address and password you provided. It then starts asking questions about your symptom status, which I won’t try answering because it would presumably screw up the data, with me not being in the UK.
As you won’t be able to find the app with the search function, the steps to installing the COVID app are:
Install Aurora Store. You can sign in with your Google account, or with an anonymous account as provided by Aurora.
Open the Play Store link to the COVID app on your FP2, your phone will ask you how you want to open the link.