Income support overpayment recovery time limits?

I have just spoken to a client who was claiming IS from 1996 to 1998 but has not claimed benefit since this time. He has received a recovery letter from the DWP for an amount of £500 relating to April 1998 to July 1998, for not submitting a med cert!!! 

Is there a maximum length of time for recovery or do we need to appeal this decsion as my client is adamant that he has all paperwork relating to this period in time including med cert copies

I believe that, as more than 6 years has passed since any payment was made or the debt acknowledged it is statute barred.  However, this does not wipe out the debt - simply means it cannot be taken to Court & enforcement action taken.

In the circumstances it would probably be best if your client sent them his proof & asked for confirmation that the debt does not exist.  He/she could also point out the limitation position.