Minor correction
Mr Wylie’s extraordinary claims require extraordinary evidence, and so far we only have his word.
No, extraordinary claims require evidence which supports them. This evidence can be quite mundane or prosaic, for example a diary, a receipt &c.
This discussion about "extraordinary evidence" is a pet peeve - it is a way of dismissing evidence which one may not like. I prefer evidence which supports claims being the requirement, remaining neutral about the extraordinariness of it.
But yes, point taken. At the moment we only have Mr Wylie's assertions, which is hardly evidence.