Hi Mark,
I think we've all been in your situation at least once in our careers as an SEO. As you've mentioned previously you've resubmitted the site via GWT etc so there's not much else you can do.
I would however recommend filing a reconsideration request if you're happy with your backlink profile and feel you would pass a manual inspection of the site. As the reconsideration request feature isn't just for sites that have been penalised.
Case and point, I had a client with 2 very similar sites targeting two seperate countries, he accidently blocked off one of his sites with a robots.txt and the site wouldn't rank properly for 2 months and the issue was only rectified after a reconsideration request.
Good luck 