In our area, teachers were on strike, but HTs weren't. They were, however instructed that the agreement was to work to rule. So no meetings after school day, not engaging in a list of addition work, like performance management etc. And a lot of HTs in the consortium also read this to mean not reporting to the county the teachers who went on strike.
Our HT, when asked if they were following this, declared that it was our bursar that does that, not them. The bursar seemed to say that it would be done but the agreement they were aware of was that the days would be taken one each payday. We're in Wales so there were only 2 strike days. I think the last one was in mid March and no pay has been taken in the time since them from striking teachers.
Is there a time limit after which the payment cannot be claimed back? I'm not unhappy to lose the pay personally, as that was clearly the decision I made knowing that they incur lost pay. But interestingly, as it's now a new academic year soon, there are some staff who have moved school, or left teaching and who cannot have the pay deducted from them if it happens after the Aug pay day as they are now not paid by our school anymore. We are local authority.