Adding to this: I've had some success (although inconsistent) using the organiser to re-import the styles as opposed to the document.updatestyles route in the macro (same as ticking & unticking the "Automatically update document styles" box).

That didn't fix the Table gallery which still showed everything without borders, however going into "modify style" for one of my styles and pressing OK without doing anything caused the gallery to refresh and bam, it was back to normal.

Obligatory "Why must we jump through to many hurdles to get this to work properly?"