Where—
an appropriate authority have served a counter-notice objecting to a blight notice in respect of any land falling within paragraph 1, 2, 3, 4 or 14 of Schedule 13 by virtue of Note (1) to that paragraph, and
the relevant plan or alterations or, as the case may be, the relevant order or scheme comes into force (whether in its original form or with modifications),
the appropriate authority may serve on the claimant, in substitution for the counter-notice already served, a further counter-notice specifying different grounds of objection.
Such a further counter-notice shall not be served—
at any time after the end of the period of two months beginning with the date on which the relevant plan or alterations come into force; or
if the objection in the counter-notice already served has been withdrawn or the Upper Tribunal has already determined whether or not to uphold that objection.