But, if no-one actually strikes - there is no question of 90 notice, or sackings or legal comeback.
90 days notice has nothing to do with industrial action (its a means of contract change, nothing more) so no difference there.
Secondly if no industrial action has actually been taken (not just called, taken) within 28 days the ballot is rendered invalid. So it doesnt get rid of the sacking/legal problem either.