Hi rswhtn,
We have not seen proof of structured data having a direct impact on general organic rankings. However, we're confident that clickthrough rate does have an impact on rankings (see Rand's Whiteboard Friday on this here, as well as Larry Kim's post). Since "rich results" (rich snippets) can impact clickthrough rate, the should then have a secondary impact on rankings.
That said, it doesn't sound like your homepage had a rich result from this use of structured data. It's also not clear whether/how Google uses this postal address data. Since it's not likely been implemented at any significant scale across the web, I'd be dubious if it were a useful ranking signal for them. It's possible, but I'd call it unlikely.
We have seen rankings fluctuate significantly across client accounts even when the pages in question have not been updated. It seems that Google's AI/Engineering team iterate on search results frequently.
So, in short, I suspect this has to do with something other than structured data.
The significant changes to the homepage may be involved (UX can have a significant impact on rankings), but these changes could very well have generated a net gain in terms of overall traffic/results in spite of this lost head term position.
Unfortunately I think easy/clear answers on this will prove evasive. If you have the data (via Ahrefs or otherwise), I'd recommend reviewing the "flux" in the top 10 search results for "clothing manufacturers" around this time. If yours is not the only result that shifted significantly in this time frame, it's like part of a larger shift in Google's ranking algorithm.
Best,
Mike