Thanks for your response
All you need to do is write to HMRc and send in the P60 with a letter, asking for a review for a tax refund. If you had other income (other than that shown on the P60) then provide the details in the letter (for the period 06/04/2012 to 05/04/2013)
HMRC will then repay you any money owed, and send your P60 back to you.
If you want to me to check whether a refund is due then please advise
1) The pay and tax details from the P60
2) Confirm you have lived in the UK for the period 06/04/2012 to 05/04/2013
3) Provide details of any other income (such as other employment, self employment, rental income,investment income, or Jobseekers Allowance for being unemployed)
If you need an address to send it to, let me know, and I can provide this, but if in the meatime you could rate the level of service, it would be appreciated, as this ensures I am paid. And any feedback and/or bonus are always welcome