Section 6 of the Principal Act is amended -

(a) in subsection (1), by the insertion after "where appropriate," of "blocked or", and

(b) by the substitution of the following subsection for subsection (2):

"(2) Where a data controller complies, or is deemed to have complied, with a request under subsection (1) of this section, he or she shall, as soon as may be and in any event not more than 40 days after the request has been given or sent to him or her, notify -

(a) the individual making the request, and

(b) if such compliance materially modifies the data concerned, any person to whom the data were disclosed during the period of 12 months immediately before the giving or sending of the request unless such notification proves impossible or involves a disproportionate effort,

of the rectification, blocking, erasure or statement concerned.".