In subsection (4) of section 8 of the [1974 c. 38.] Land Tenure Reform (Scotland) Act 1974 (property on long lease not to be used as private dwelling house) in the definition of " long lease " there shall be inserted at the end the following—
“but, in relation to a lease granted before 1st September 1974, does not include its renewal (whether before or after the commencement of section 1 of the Law Reform (Miscellaneous Provisions) (Scotland) Act 1985) in implement of an obligation in or under it.”