11.—(1) The amendments to the 1996 Act made by Part III of Schedule 4 to the Act relating to protection from detriment shall have effect only in relation to an act or failure to act which takes place on or after 15th December 1999.
(2) For the purposes of sub-paragraph (1)—
(a)where an act extends over a period, the reference to the date of the act is a reference to the last day of that period, and
(b)a failure to act is to be treated as done when it was decided on.
(3) For the purposes of sub-paragraph (2), in the absence of evidence establishing the contrary an employer shall be taken to decide on a failure to act—
(a)when he does an act inconsistent with doing the failed act, or
(b)if he has done no such inconsistent act, when the period expires within which he might reasonably have been expected to do the failed act if it was to to be done.