How to stop empty lines being printed in address labels created from the Address Data Source Wizard?

How to stop empty lines being printed in address labels, created in Libra Office Writer, from the Address Data Source Wizard?
Some addresses in the data source don’t have a house name and these appear as empty lines in the labels.

The solution is often simple, finding it is the hard bit.
I was hoping someone may know how to do it other than by manual editing…