45(1)Liability to a penalty under paragraph 39 or 40 does not arise if the person satisfies HMRC or (on appeal) the First-tier Tribunal that there is a reasonable excuse for the failure or the obstruction of an officer of Revenue and Customs.
(2)For the purposes of this paragraph—
(a)an insufficiency of funds is not a reasonable excuse unless attributable to events outside the person’s control,
(b)where the person relies on any other person to do anything, that is not a reasonable excuse unless the first person took reasonable care to avoid the failure or obstruction, and
(c)where the person had a reasonable excuse for the failure or obstruction but the excuse has ceased, the person is to be treated as having continued to have the excuse if the failure is remedied, or the obstruction stops, without unreasonable delay after the excuse ceased.