People will be getting bored of this but I’ll say it one last time and leave the thread to get back to the actual title.
I was sat sat next to people who were about to be unfairly dismissed. And I have been a witness in employment tribunals.
If you are sacked for taking part in a correctly organised trade union dispute (whether that is strike or action short of strike) then that is unfair dismissal.
However your recourse is exactly the same whether you are sacked for striking or you are sacked for any other unfair reason. Just because the strike is legal doesn’t mean you can’t be unlawfully dismissed.
Your former employer will just suck up the “fine” and move on.
It really isn’t hard to understand. Anyone can be sacked. It’s up to an employment tribunal to sort out the details much much later.