Please see the SA Manual link, if the return is filed more than 45 days before the liability due date then an SA statement would be issued. So as mentioned in a previous post the SA statements start to be issued mid-December from paper returns filed before 31st October and any returns filed online by that point.
if you contact the HMRC helpline they should be able to issue out a specific form for redundancy payments and claiming a refund on them and then you would enter the refund on the SA return when it is completed so that a further refund is not given
My answers
Please see the SA Manual link, if the return is filed more than 45 days before the liability due date then an SA statement would be issued. So as mentioned in a previous post the SA statements start to be issued mid-December from paper returns filed before 31st October and any returns filed online by that point.
https://www.gov.uk/hmrc-internal-manuals/self-assessment-manual/sam131100
From the HMRC website
https://www.gov.uk/claim-tax-refund/youve-stopped-work
if you contact the HMRC helpline they should be able to issue out a specific form for redundancy payments and claiming a refund on them and then you would enter the refund on the SA return when it is completed so that a further refund is not given