YOU CAN GIVE UP A 2ND SECTOR VALIDATION ABOVE MUR WHENVER YOU WANT
Yes if you read my post 1699 I said that
FOR WHATEVER REASON YOU WANT
Yes but if it could be considered as industrial action there are a number of pre-requisites including a properly constituted ballot for that action to be official. If it's unofficial you can still do it but you won't enjoy any of the protections that come with the official tag.
That is not industrial action per se.
Actually it might be. The relevant legislation is not very specific as to what constitutes industrial action so without very detailed knowledge of previous cases and perhaps a court judgement you won't know