Battery doorbell - not ringing iPhone

I’m sure this will have been covered but I can’t find an exact match

In short, when someone presses my battery doorbell, it doesn’t ring on my iPhone. I get notifications and I can live stream/ communicate fine it just doesn’t let me know when someone rings the bell if I am not at home. The Homebase chime works fine

Generally I am very happy with the set up but I feel I should be being notified on my phone when the doorbell is pressed

Any ideas?