Hi.If you would like your 2012/13 and 2013/14 tax positions reviewed, all you need to do is to send your P60s to the tax office (see below re address) with a letter and ask for a P800 tax calculation for each tax year. If you are overpaid, you will get the excess tax back. If you owe tax, you will either need to pay it or have it collected through your tax coding. HMRC may issue a P800 automatically but they may take months to do it so send your P60s to them. Keep a copy of your letter and your P60.As for your tax code, call the tax office on the number here, explain your situation to them, ask them to review your tax code for the current tax year 2014/15 and to make any necessary amendments. You should be on tax code 1,000L assuming you have only one job. When you call the tax office, ask for the address of the tax office that you should send your P60s to as there several possibilities.I hope this helps but let me know if you have any further questions.