i know this has been covered before, but is a minefied of accounting, i have some good news for a change. after having three employers in a financial year - mob service, TA and civi, i wrote to the national insurance office enquiring whether i might have paid too much. they sent me out the forms, they were filled in from my p60's, sent away and within 2 weeks i received a cheque in the post. all very simple,no accountants needed. therefore i urge you to try the same, you might not get anything back but then again you might.