Am I owed money from the inland revenue?

5 years ago I went to the Inland Revenue about national insurance and they did some checks and came back and told me that I had been overpaying my national insurance and that in order to claim it back I needed to provide them with starting and finishing dates for all my jobs. I have had quite a few jobs and never got round to doing this. Would this still be the case that I am owed money and how do I find out?