1. Don't use the AddressBlock - insert the individual mergefields where you want them.
2. Don't us a numeric picture switch in the 'postal' mergefield - all that will do is mess up the alpha-numeric post codes.
3. Read
Mailmerge Data Format Problems in the
Mailmerge Tips & Tricks 'Sticky' thread at the top of this forum:
https://www.msofficeforums.com/mail-...ps-tricks.html