Section 19B does not apply to—
(a) a decision not to institute criminal proceedings and, where such a decision has been made, any act done for the purpose of enabling the decision whether to institute criminal proceedings to be made;
(b) where criminal proceedings are not continued as a result of a decision not to continue them, the decision and, where such a decision has been made—
(i) any act done for the purpose of enabling the decision whether to continue the proceedings to be made; and
(ii) any act done for the purpose of securing that the proceedings are not continued.