"In the circumstances, the first step must be to analyse the evidence of the transferor's intention. The evidence may be biased, uncorroborated, contradictory or difficult to comprehend. But the relevance, reliability, credibility and persuasiveness of the evidence must be evaluated, no matter how challenging the exercise may be. Indeed, where the transferor is available to give direct evidence of his intention, it is difficult to conceive when the application of the presumptions will be necessary."