'[37] In our judgment, no new information, of fact or law, is required for there to be a discovery. All that is required is that it has newly appeared to an officer, acting honestly and reasonably, that there is an insufficiency in an assessment. That can be for any reason, including a change of view, change of opinion, or correction of an oversight.'
'The courts are ever mindful that their constitutional role in this field is interpretative. They must abstain from any course which might have the appearance of judicial legislation. A statute is expressed in language approved and enacted by the legislature. So the courts exercise considerable caution before adding or omitting or substituting words. Before interpreting a statute in this way the court must be abundantly sure of three matters: (1) the intended purpose of the statute or provision in question; (2) that by inadvertence the draftsman and Parliament failed to give effect to that purpose in the provision in question; and (3) the substance of the provision Parliament would have made, although not necessarily the precise words Parliament would have used, had the error in the Bill been noticed. The third of these conditions is of crucial importance. Otherwise any attempt to determine the meaning of the enactment would cross the boundary between construction and legislation …'