In this Act "associated operations" means, subject to subsection (2) below, any two or more operations of any kind, being—
whether those operations are effected by the same person or different persons, and whether or not they are simultaneous; and "operation" includes an omission.
The granting of a lease for full consideration in money or money's worth shall not be taken to be associated with any operation effected more than three years after the grant, and no operation effected on or after 27th March 1974 shall be taken to be associated with an operation effected before that date.
Where a transfer of value is made by associated operations carried out at different times it shall be treated as made at the time of the last of them; but where any one or more of the earlier operations also constitute a transfer of value made by the same transferor, the value transferred by the earlier operations shall be treated as reducing the value transferred by all the operations taken together, except to the extent that the transfer constituted by the earlier operations but not that made by all the operations taken together is exempt under section 18 above.