" If a person who, apart from this subsection, would be liable to a surcharge under subsection (4) above satisfies the Commissioners or, on appeal, a tribunal that, in the case of a default which is material to the surcharge— (a) the return or, as the case may be, the VAT shown on the return was despatched at such a time and in such a manner that it was reasonable to expect that it would be received by the Commissioners within the appropriate time limit, or (b) there is a reasonable excuse for the return or VAT not having been so despatched, he shall not be liable to the surcharge and for the purposes of the preceding provisions of this section he shall be treated as not having been in default in respect of the prescribed accounting period in question (and, accordingly, any surcharge liability notice the service of which depended upon that default shall be deemed not to have been served)."
"(1) For the purpose of any provision of sections 59 to 70 which refers to a reasonable excuse for any conduct— (a) an insufficiency of funds to pay any VAT due is not a reasonable excuse; and (b) where reliance is placed on any other person to perform any task, neither the fact of that reliance nor any dilatoriness or inaccuracy on the part of the person relied upon is a reasonable excuse. (2) In relation to a prescribed accounting period, any reference in sections 59 to 69 to credit for input tax includes a reference to any sum which, in a return for that period, is claimed as a deduction from VAT due."