PAYE

I have just taken on a personal tax client who never has to submit a tax return because he is on PAYE. He came to me because he has a new source of income and has to submit a tax return for the year 2011/2012. I also review his PAYE for previous years and noticed that for the year 2006/2007 and 2007/2008 he was given a BR M1 PAYE code. Obviously, the time limit for claiming back tax is four years and therefore those years are time expired. Is there any way to make a claim for overpayment of tax and under which section should I refer the Revenue to.