522L is the correct standard code for a taxpayer under 65 for the year ended 5th April 2008.
The confusion arose because the original post asked what is should be and everyone presumed that meant NOW when in fact it meant last tax year. Badly worded question.
The correct code now would be 604L but that's due to the Chancellor amending it recently under pressure about the removal of the 10% band. It would have been 543L initially and may well still be for many of us.