“The Court of Appeal shall, in considering whether to receive any evidence, have regard in particular to -- (a) whether the evidence appears to the court to be capable of belief; (b) whether it appears to the court that the evidence may afford any ground for allowing the appeal; (c) whether the evidence would have been admissible in the proceedings from which the appeal lies on an issue which is the subject of the appeal; and (d) whether there is a reasonable explanation for the failure to adduce the evidence in these proceedings.”