“The appellant’s clerk, who submitted the return, cannot say one way or the other whether an automated acknowledgement was received from HMRC, although there is now nothing on her computer, she considers it possible that she might have deleted it. Certainly, had there been any doubt in her mind that she had indeed correctly submitted the return then of course she would have contacted HMRC to check, and the fact that she did not is further evidence of her believing, in good faith, that she had indeed filed the return.”