Hi Ben,
That's a fantastic response, thank you for taking the time to look.
You're right, I was going to mention fasteners being a boring industry - I bookmarked the very same webinar a few days ago but have only seen a small amount of it so far.
The reason I was looking at Penguin etc is that on those terms we've gone from 1st page to oblivion in recent months. There are sites above us with no links or activity, and that aren't relevant. Does that point to a bad backlink profile in that case? As you say, I'll continue with removing the poor quality directory links as that can't hurt, they won't have been passing value anyway.
I'll send removal requests twice and then disavow if nothing changes after a few weeks. Is there anything specific notes-wise I need to put in a disavow (ie 'sent removal request 8/11, no response') or is just a list of domains / links? I notice Google has changed the way they look at things - you can check if any manual spam actions have been taken directly in Webmaster Tools now, negating the need for a reconsideration request. Am I right in thinking that all we can do with Google is disavow?
First stop is to take a look at the 'content marketing in boring industries' webinar, and then I'll formulate a new content marketing strategy as you suggested.
Thanks for your advice.
Anything further you or anyone else can add would be greatly appreciated.
Best Regards,
Stephen