(1) Subject to sections 514 and 515(6), any reference in this Chapter to the locked-in value of any of a participant's shares at any time shall be construed as follows:
(a) if before that time the participant has become chargeable to income tax by virtue of section 513 on a percentage of the amount or value of any capital receipt (within the meaning of that section) which is referable to those shares, the locked-in value of the shares shall be the amount by which their initial market value exceeds the amount or value of that capital receipt or, if there has been more than one such receipt, the aggregate of those receipts, and
(b) in any other case, the locked-in value of the shares shall be their initial market value.
(2) Where the trustees dispose of any of a participant's shares at any time before the release date or, if it is earlier, the date of the participant's death, the participant shall, subject to subsections (3) and (4), be chargeable to income tax under Schedule E for the y
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