It also looks like all the other sites follow the exact same HTML conventions and styling. Some are done in PHP and some in ASP (...) Since you found "birdrating.com" on themeforest, and since they all follow similar conventions, it's plausible that the others come from themeforest as well.

http://www.theoldcheesefactory.com/

http://birdrating.com/

http://www.demilles.co.uk/

http://buildingdispute.com/

http://altek-al.com/

Thanks!