A notice to treat under section 17 of the Lands Clauses Consolidation (Scotland) Act 1845 shall, for the purposes of any compulsory purchase to which the provisions of the first Schedule to the Acquisition of Land (Authorisation Procedure) (Scotland) Act 1947 apply, cease to have effect at the end of the period of three years beginning with the date on which it is served unless—
If the person interested in the land, or having power to sell and convey it, and the acquiring authority agree to extend the period referred to in subsection (1) of this section, the notice to treat shall cease to have effect at the end of the period as extended unless—
Where a notice to treat ceases to have effect by virtue of subsection (1) or (2) of this section, the acquiring authority—
The amount of any compensation payable under subsection (3) of this section shall, in default of agreement, be determined by the Lands Tribunal for Scotland.
Compensation payable to any person under subsection (3) of this section shall carry interest at the rate prescribed under section 40 (rate of interest after entry on land) of the Land Compensation (Scotland) Act 1963 from the date on which he was entitled to be given notice under that subsection until payment.