Were daily penalties for late ATED return charged retrospectively?

The taxpayer a family business owned caravan parks. In 2017 it bought a cottage to operate as a holiday let. Its adviser was aware of the purchase but was late submitting the annual tax on enveloped dwellings returns for 2017-18 and 2018-19. HMRC charged a flat-rate penalty for the original failure and daily penalties.

The taxpayer appealed and after a review HMRC withdrew the penalties for 2017-18 because they had been issued on the wrong date.

At the First-tier Tribunal the judge said reliance on its adviser was not  reasonable excuse. The failure of its professional adviser to take the correct action was a matter between them and the taxpayer. The fixed penalties therefore stood.

However on the daily penalties the issue was whether these could be imposed retrospectively before HMRC had warned the taxpayer of the possibility of a penalty. The judge...