Christmas again and usual label printing job.

This year I am using Word 2019 for the first time having upgraded from 2010 at last and I have a problem with MailMerge form an Outlook contacts list. The spacing on the labels is wrong. Firstly, by default, each line has too much space and the label registration drifts. If I change before/after spacing to zero the labels look OK on the screen but the registration still drifts.

I print on A4 label sheets.

Any ideas?