“ For the purposes of this act, the person shall be deemed not to have failed to do anything required to be done within a limited time if he did it within such further time, if any, as the board or the tribunal or officer concerned may have allowed; and where a person had a reasonable excuse for not doing anything required to be done he shall be deemed not to have failed to do it unless the excuse ceased and, after the excuse ceased, he shall be deemed not to have failed to do it if he did it without unreasonable delay after the excuse had ceased… ”
“( 1) Liability to a penalty under any paragraph of this Schedule does not arise in relation to a failure to make a return if [the taxpayer] satisfies HMRC or (on appeal) the First-tier Tribunal or Upper Tribunal that there is a reasonable excuse for the failure. (2) for the purposes of sub-paragraph (1) - (a) an insufficiency of funds is not a reasonable excuse, unless attributable to events outside P's control, (b) where P relies on any other person to do anything, that is not a reasonable excuse unless P took reasonable care to avoid the failure, and (c) where P had a reasonable excuse for the failure but the excuse has ceased, P is to be treated as having continued to have the excuse if the failure is remedied without unreasonable delay after the excuse ceased .”
“ An assessment, warrant or other proceeding which purports to be made in pursuance of any provision of the Taxes Acts shall not be quashed, or deemed to be void or voidable, for want of form, or be affected by reason of a mistake, defect or omission therein, if the same is in substance and effect in conformity with or according to the intent and meaning of the Taxes Acts, and if the person or property charged or intended to be charged or affected thereby is designated therein according to common intent and understanding.”
“ Calculating your tax – if we receive this paper tax return by 31 October 20[ ] or if you file online, we’ll do the calculation for you and tell you how much you have to pay (or what your repayment will be) before 31 January 20[ ]. We’ll add the amount due to your Self Assessment Statement, together with any other amounts due. Don’t enter payments on account, or other payments you have made towards the amounts due, on your tax return. We’ll deduct these on your Self Assessment Statement. If you want to calculate your tax, ask us for the ‘Tax calculation summary’ pages and notes. The notes will help you work out any tax due or repayable, and if payments on account are necessary.”