RM5504 | RO instructions: When you have repaid or decided not to repay
From HM Revenue & Customs · Repayment Claims Manual
The time limit for making a claim is usually four years but an RA can use RC to register claims for the current year and the previous seven years.
If you get a claim which is too old to register in RC
apply the following instructions
and
take the additional steps at RM5508 onwards.
In every case
check that the claimant has been set up
use CZ to enter any amended claimant or agent details shown on the claim form
if the claim is unsigned
see RM2552
and
return it for signature
If you decide the claim is in time (RM5512) or if HMRC Trusts Head Office Edinburgh tell you to accept the claim (RM5520)
When the payable order has been issued or when you have decided not to repay close the entry in the register (RM5536).
In addition refer to instructions at