In section 129 of the Housing Act 1985 (discount on exercise of right to buy), for subsections (1) and (2) substitute—
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A conveyance or lease containing the covenant required by any of the provisions mentioned in subsection (3) which was executed before the amendments made by that subsection came into force shall, provided no amount was then or had previously been payable under the covenant, have effect with such modifications as may be necessary to bring it into conformity with the amendments.