Veritas 8 Compact Control Panel Wont Set?

We had this new alarm and the above control panel fitted by a specialist local alarm company. It has worked perfectly until yesterday when it just wouldn’t set. I checked the whole house and shut all doors / windows, etc. Basically the 10th LED is solid green (closest to the power LED) and the power LED is solid green as well.

If I enter anything it just does a loud single beep but nothing else. What could this be?

Thanks