After I just inadvertently flashed a policeman.

In bath, DS in bedroom playing with Lego and doorbell goes. DS flies into bathroom to tell me and ask who it is .
We live in a small apartment block with 4 flats. There is front and back outer doors which we use to buzz in visitors so presumed whoever it was was a door to door and had harassed neighbours previously.
He leaves and I lay back down and bell goes again.