RM1012 | RA action: If the claim is unsigned
From HM Revenue & Customs · Repayment Claims Manual
If the claim is unsigned do not cancel any vouchers.
Send the claim back to the claimant for signature as follows.
In every case enclose any vouchers and/or documents.
In addition if there is no reference quoted on the claim
find out where the claim will be dealt with
check TI
if no reference on TI ask the allocation officer
tell the claimant
where to submit the signed claim
and
if found on TI , the reference to quote on the claim form