Thanks for your question - I am Sam and I am one of the Uk tax experts here on Just Answer.
HMRC can only go back 4 years (so to 201) but what makes you think you might be due a tax refund, have you had gaps in between employment, or unemployment - please advsie further
If you are not sure, but just want HMRC to review then you will need to write to them to check back your previous tax year position and you quote your National Insurance number and write to
Pay As You Earn and Self Assessment
HM Revenue and Customs
Do let me know if I can assist further