If the people who hired you to design a website have been dodgy and unreliable about payment, here's a little stunt that will shock their wallets and open their wallets: scrap the entire site and kindly demand payment on the website's front page. Your payment should come soon after.
Our own Jesus Diaz has admitted to using this tactic on delinquent clients in his former life as a designer, and many designers keep this sort of stunt as a last-resort method in order to get paid. From what I can tell, Freshbaked UK -- the delinquent company in question -- is a PR/marketing agency who doesn't appreciate the job of a designer and is in deep doodoo itself. Tsk, tsk, guys. I'm sure you guys know where to find your website. [Freshbaked UK via @ZachInglis]