Sections 20(1) and 21 do not apply to discrimination on grounds other than those of race or ethnic or national origins in either the provision by a person of accommodation in any premises, or the disposal of premises by him, if—
(a) that person or a near relative of his (“the relevant occupier") resides, and intends to continue to reside, on the premises; and
(b) there is on the premises, in addition to the accommodation occupied by the relevant occupier, accommodation (not being storage accommodation or means of access) shared by the relevant occupier with other persons residing on the premises who are not members of his household; and
(c) the premises are small premises.
Premises shall be treated for the purposes of this section as small premises if—
(a) in the case of premises comprising residential accommodation for one or more households (under separate letting or similar agreements) in addition to the accommodation occupied by the relevant occupier, there is not normally residential accommodation for more than two such households and only the relevant occupier and any member of his household reside in the accommodation occupied by him;
(b) in the case of premises not falling within paragraph (a), there is not normally residential accommodation on the premises for more than six persons in addition to the relevant occupier and any members of his household.