A secure tenant may in his notice under section 122 require that not more than three members of his family who are not joint tenants but occupy the dwelling-house as their only or principal home should share the right to buy with him.
He may validly do so in the case of any such member only if—
that member is his spouse , is his civil partner or has been residing with him throughout the period of twelve months ending with the giving of the notice, or
the landlord consents.
Where by such a notice any members of the tenant's family are validly required to share the right to buy with the tenant, the right to buy belongs to the tenant and those members jointly and he and they shall be treated for the purposes of this Part as joint tenants.