4(1)For the purposes of this Part consideration attributable—U.K.
(a)to two or more land transactions, or
(b)in part to a land transaction and in part to another matter, or
(c)in part to matters making it chargeable consideration and in part to other matters,
shall be apportioned on a just and reasonable basis.
(2)If the consideration is not so apportioned, this Part has effect as if it had been so apportioned.
(3)For the purposes of this paragraph any consideration given for what is in substance one bargain shall be treated as attributable to all the elements of the bargain, even though—
(a)separate consideration is, or purports to be, given for different elements of the bargain, or
(b)there are, or purport to be, separate transactions in respect of different elements of the bargain.