Where an enactment which is not to come into force immediately on the passing or making thereof confers power—
(a)to make appointments;
(b)to hold elections;
(c)to make statutory instruments or issue statutory documents;
(d)to publish documents or give any notices;
(e)to prescribe forms;
(f)to give directions; or
(g)to do any other act or thing;
that power may, for the purpose of making the enactment effective upon its commencement, be exercised at any time after the passing or making thereof, but, except in so far as may be necessary or expedient for that purpose, a statutory instrument or statutory document made under that power shall not have effect before the commencement of the enactment conferring the power.