In any case where the rights and powers of a parent of a patient, being a child or young person, are vested in a local authority or other person by virtue of—
(a)section 17 of the [1968 c. 49.] Social Work (Scotland) Act 1968 (which relates to children in respect of whom parental rights have been assumed under section 16 of that Act); or
(b)section 3 of the [1980 c. 5.] Child Care Act 1980 (which makes corresponding provisions in England and Wales); or
(c)section 10 of the said Act of 1980 (which relates to the powers and duties of local authorities in England and Wales with respect to persons committed to their care);
that authority or person shall be deemed to be the nearest relative of the patient in preference to any person except the husband or wife (if any) of the patient, and except, in a case where the said rights and powers are vested in a local authority by virtue of subsection (2) of the said section 17 or subsection (1) of the said section 3, any parent of the patient not being the person on whose account the resolution mentioned in that subsection was passed.