STSM153060 | Compliance: Stamp Duty penalties: documents dated in pencil
From HM Revenue & Customs · Stamp Taxes on Shares Manual
The date of execution of an instrument must be entered in ink or typescript.
HMRC will not assess the duty and penalty upon a document until this has been done. Where the date has been entered in pencil HMRC will return the document and ask that it be inked in.