Thank you Remus for your repsonse.
There are no manual actions in webmaster tools.
Open Site Explorer picks up the bad links, and google only lists a small amount. There are approx 4000, so its not realistic to approach every webmaster - saying this we have approached some.
Ive seen that Penguin changes released at the end of May 2013 have targetted "unnatural linking" and this incident happened over a few weeks around April/May 2013. So it is likely we were affected.
Like you said if they were followed at some stage and as a result we were indeed affected, then surely we have a case for Google to fairly reposition us?
There is no doubting this attack was deliberate as I've found source code on some of the affected sites which lists not only our website but other compititors in the industry. In fact every major player except for one, which is highly suspicious in itself. Also among the affected links are links to forums and discussion boards to bad reviews of the company which does not have unnatural links.
Its a tough one I know, my first priority is to restore our SEO ranking with Google. Ive researched Googles recommended actions to request reconsideration, but there are no manual actions so Im not sure how to submit that request.
Its seems extremely unfair that someone elses deliberate actions to effectively sabotage your ranking gets great positioning where you get penalised.