STSM142135 | Stamp duty and SDRT administration: SDRT administration: penalties if you miss an SDRT deadline
From HM Revenue & Customs · Stamp Taxes on Shares Manual
Penalties are charged for late Stamp Duty Reserve Tax (SDRT) notifications (Schedule 55 FA2009, for notifications due on or after 1 September 2014), and for late payment (Schedule 56 FA2009, from 1 January 2015).
Information on SDRT late notification and payment penalties is available:
on gov.uk
and in the Compliance Handbook for:
late payment penalties