" Applicant was in a dilemma whether to plead guilty or not guilty ?" Would that be about a change of position regarding any parole if he'd have pleaded guilty ? I'm not sure I understand that bit.
No, the Judgement indicates that there is no evidence that Jeremy has reduced his level of dangerousness.
If he had undertaken offence related work, then there may be evidence that they could see his level of dangerousness had reduced (or not).
Jeremy had not undertaken any offence related work as he claimed it would not be appropriate given his position in claiming he was innocent.
The judgement concludes that regardless of the reasons why Jeremy had not undertaken offence related work, the fact remained that there was nothing that the court could rely on to show his level of dangerousness had reduced.
The Wednesbury irrational, or unreasonable, refers to a case from 1947 and is cited as a level of reasonableness.