Hopefully this will help.

A new doorbell came this morning (the reason for using the drill) and I've mounted it on the mailbox for the postie to ring when we have a reg that needs signing.

They just blow the horn and we can't hear it from our playroom so we've been monitoring the camera for years, this should ease our concern but I will have to tell them about it ASAP.

The rubber flap is to prevent water ingress, hopefully.