Do an SEO audit on our website OneDirection.net to find out ranking problems

I run the website [login to view URL] which is an extremely popular One Direction news & fan site. We used to rank on page 1 of [login to view URL] and [login to view URL] for "one direction", but our rankings have slowly dropped over the last 12-18 months, and we're now on page 2 of [login to view URL], and page 3-5 of Google.co.uk. We suffered a large drop in traffic after Google Penguin in April 2012, and since then we've been trying to clean up our link profile. We have a decent number of quality sites that link to us including [login to view URL], [login to view URL], TheDailyBeast and others, but we think our link profile still might need to be stronger. The site currently receives 750,000 visitors per month, and can vary in daily traffic from 20k-50k. Obviously we rank for many more keywords than just "one direction", but we feel if we can improve this then naturally our rankings for our many other longer-tail keywords should also improve. This keyword in particular can generate a lot of traffic. We would also like to improve our rankings in other countries ([login to view URL], [login to view URL] etc). We've spent a lot of time cleaning up our on-site SEO and we think its quite strong, but obviously a second pair of eyes might also be able to find problems still. Please note we have NEVER received an unnatural links warning from Google. We have however submitted a disavow file with over 200 poor quality domains listed. We're looking for someone with EXTREMELY GOOD knowledge of on-site SEO and off-site link profiling to take an in-depth look at our website and let us know how we can improve rankings. Thanks, Chris.