tedster - 11:52 pm on Aug 5, 2012 (gmt 0)
The reply we got (6 days after submit) stated that there were no manual actions against the site.
If the site really has a Penguin demotion (and only that), then response is what you will get. And then at least you know there is no penalty and your analysis pegging it as a Penguin problem has been correct.
I agree with you, there's no reason to expect any site to remove a link they didn't have any involvement in placing. Google may or may not be tangled up at present, but falsifying what your client says won't help sort things out any better.