SolvedSDLTM54110 | Overpayment relief: Exclusions: Case A mistake concerning a relief or election
From HM Revenue & Customs · Stamp Duty Land Tax Manual
Overpayment relief is not due where the amount paid, or due, is excessive because of a mistake
in any other formal claim or election
in making any other claim or election, or failing to do so.
HM Revenue & Customs (HMRC) may in limited circumstances accept a late claim or election, see Assessment Claims Manual (SACM) page SACM10035 @ ).