My website has been ranking in 1st or 2nd for a number of local keywords i.e. 'Liverpool Accountants', 'Accountants Liverpool' and 'Accountants in Liverpool' from March 2013 up until around August 20th when the homepage suddenly dropped out.
The homepage started ranking again in September back in 1st for all keywords and then in the second week of October in disappeared again and hasn't returned.
All the backlinks linking to the website are good quality and relevant, no spam at all.
The anchor text analysis draws up no problems either.
The only thing I could perceive to be an issue is that the homepage scrapes content from 3 other sections of the website - a short paragraph from the About Us section, the Case Study section and another page. Could it be that Google is filtering the homepage out of search results because it perceives the content to be duplicated?