What is the scope of appellate review of a lower court's decision on a judicial review application?

The respondent relies upon the decision in Prince Edward Island Public Service Association v. Holland College (1986), 1986 CanLII 179 (PE SCAD), 60 Nfld. & P.E.I.R. 82; 181 A.P.R. 82 (P.E.I.C.A.) as authority for the proposition that an appellate court should not interfere with a reviewing judge's decision on judicial review unless the reviewing judge could not reasonably have reached the conclusion he or she did. The scope of appellate review of lower court decisions arising from judicial review applications requires clarification as I do not think this decision, which is frequently relied upon, accurately reflects what the scope of review is, or should be.