The meta robots block sounds like it's a block from your CMS or something in your header include file or something. I would check on the pages that show as blocked to see if there's any noindex sort of code in those pages. Other then that, shift in rankings could be based on your competition optimizing for the same set of keywords. I would recommend to spend some time analyzing the backlinks of the competition and see if you can gain some of those kinds of links.
On a side note: It also looks like you own both the .com and the .com.au site. The .com is hosted in AU and the .com.au is hosted in USA. Did you intend to do it the other way around ? I would imagine your rankings for the .com.au get better if it was hosted in Australia instead of USA.