61A. The Minister may, by order in the Gazette, amend the Schedule, except that any other personal identifier so prescribed in the order must —
(a)
be an image of, or a measurement or recording of, an external part of the human body or a person’s voice; and
(b)
not be an identifier the obtaining of which would involve the taking of an invasive sample within the meaning given by section 8 of the Registration of Criminals Act 1949.