82 It was not seriously in issue that, at the time he executed the will, the deceased possessed the requisite testamentary capacity. Nor was it in issue that the deceased intended the document that he signed to be his last will and testament. The critical issue was whether he knew and approved the contents of the document that he signed and, in particular, whether he knew and approved of the disposition of the 'front orchard' to the second respondent. That critical question tends to blur the line between the question of probate and the question of construction. It also brings into play the difficult question whether, and to what extent, extrinsic evidence is admissible in proceedings of this nature. Again as a broad general statement, extrinsic evidence is admissible to establish testamentary intention, a necessary pre-requisite for a grant of probate: In re Resch's Wills Trusts [1967] 2 NSWR 706; [1969] 1 AC 514, 547, Re Luck (deceased) [1977] WAR 148, 150. But a court of construction will not usually admit extrinsic evidence as to the testator's intentions: Re Smith; Equity Trustees Executors & Agency Co Ltd v Smith [1939] VicLawRp 33; [1939] VLR 213, 218. In the context of this case, those difficulties were brought into sharp focus by the description of the subject land in the will as 'Property known as Lot 2D15522 Fisher Road Bindoon WA' and by the evidence of Ms Treasure, Ms Lefroy and Ms Thompson. I will have more to say about those questions later in these reasons.