Penalties for failure to pay on time: rules for specific taxes: Stamp Duty Reserve Tax (SDRT): failure to pay all or part of amounts due - total penalties
The overall penalties for the chargeable period are the total of
- any initial penalty - 5% on tax unpaid at the penalty date, see CH154530,
- any 5 month further penalty - 5% on tax unpaid 5 months after the penalty date, see CH154540 and
- any 11 month further penalty - 5% on tax unpaid 11 months after the penalty date.
See the example at CH154560.