17.—(1) Liability to a penalty under regulation 13, 14 or 16 does not arise if the person satisfies HMRC or (on an appeal notified to the tribunal) the tribunal that there is a reasonable excuse for the failure.
(2) For the purposes of this regulation neither of the following is a reasonable excuse—
(a)that there is an insufficiency of funds to do something,
(b)that a person relies upon another person to do something.
(3) If a person had a reasonable excuse for a failure but the excuse has ceased, the person is to be treated as having continued to have the excuse if the failure is remedied without unreasonable delay after the excuse ceased.