The toilets are simply being locked out of use as they're no longer allowed due to lack of retention tanks. They've been locked for a while now, but when the tanks etc have been flushed through they're being permanently taken out of use to avoid crew confusion. A proportion of the fleet is already off lease, and the rest will be following this year. There's no funding to keep them.I notice that on one of Northern's 153's, the door handle to the toilet has been permanently plated over.
I regard this as a positive as it shows a longer term commitment to running 3 carriage services over two carriage ones. They need to be getting all of their 153's ready for longer term use.