The wife DOES acquire husband's PRR history and her CG should be calculated in the same way as husband’s, no need to transfer the ex-private residence to him. See TCGA s.222(7).
I disagree. You have to work through Section 222(7) in stages.
First part of 222(7) - if different interests in an asset have been acquired at different times, then in simple terms the earliest relevant acquisition date is used. Then it goes into (a) and (b) for a husband/wife living together:
222(7)(a) - talks about inter-spouse transfers of an only or main residence. It is written in the present tense "which
is their only or main residence" (my emphasis), not which was or which has been ... And this paragraph is particularly concerned with a transfer on death.
222(7)(b) - effectively matches periods of residence where they are not the same. But (b) only applies if (a) applies - i.e. that it was an only or main residence for both at the time of transfer. And this means true "residence", not staying there temporarily for a month just to gain a tax advantage. And remember that (a) appears to have been written with death in mind (but it does not apply exclusively to such cases).
So in this case Section 222(7) does not transfer the ownership history from husband to wife, since the property was not as a matter of fact the wife's only or main residence at the time of transfer.