There are many reasons why you may have overpaid tax to HMRC (Her Majesty's Revenue and Customs), making you eligible to claim tax back. For example, you may have been given the wrong tax code, your employer may have deducted your tax incorrectly...
You may well think you are due a tax refund but not have sought to address the issue yet because you believe the process will be too complicated. After all, dealing with matters like this does not fall under most people's experience and on the fac...