That box had a load of girders shoved through it years ago to try and prevent it falling into the stream behind it.
Wooden boxes are notorious for movement.
It had a bit of an odd history, ceasing to be a block post back in the 30s or so but still remaining as a crossing box working signals.
Not sure when it will be put out of it's misery, the story changes frequently as to whether it might go to a preserved line, but the dead flower tubs add little to the local ambience where the crossing keepers used to be keen to keep it presentable, it's just a sad corpse now.