“ there must have been a mistake as to an existing fact, including a mistake as to the availability of evidence on a particular matter; the fact or evidence must have been "established", in the sense that it was uncontentious and objectively verifiable; the appellant (or his advisors) must not have been responsible for the mistake; and the mistake must have played a material (though not necessarily decisive) part in the tribunal's reasoning.”
‘ One situation which may give rise to a finding of irrationality or procedural unfairness is where a panel has made a decision in the absence of an important piece of evidence which might have made a difference to the decision and which the panel might reasonably have been expected to obtain (adjourning the hearing, if necessary), for that purpose.’