Annexe Discount: in respect of a dwelling which —
(a) forms part of a single property which includes at least one other dwelling; and
(b) is being used by a resident of that other dwelling as part of their sole or main residence; or
(c) is the sole or main residence of a relative of the person who is liable to pay council tax in respect of that other dwelling.
A person (“P”) is to be regarded as the relative of another if P—
(i) is the spouse or civil partner of that person, or
(ii) is that person’s parent, child, grandparent, grandchild, brother, sister, uncle or aunt, nephew or niece, great-grandparent, great-grandchild, great-uncle, great-aunt, great-nephew or great-niece,
or
(iii) is that person’s great-great-grandparent, great-great-grandchild, great-great-uncle, great-great-aunt, great-great-nephew or great-great-niece; and
(aa) a relationship by marriage or civil partnership shall be treated as a relationship by blood;
(bb) a relationship between two persons who are not married but are living together as a married couple shall be treated as a relationship by marriage and a relationship between two persons of the same sex living together as if they were civil partners shall be treated as a relationship by civil partnership; and
(cc) the stepchild of a person shall be treated as that person’s child;
(dd) the child of the civil partner of a person (‘A’) shall be treated as A’s child.