I don't think Paul Barron & Ian Mills will be particularly upset about the ATCO branch withdrawing from the Working Together Agreement.
They are not daft, I imagine they know exactly what savings they want to make in the Ops rooms and they will go about it in a methodical manner.
Unlike previous managements they are simply not scared of ATCOs; they will have walked around the Ops rooms and seen ATCOs dressed for the beach in their long shorts and flip flops.