I would look under grips as the countersunk were already removed, the finish is typical for english countries refurbishment is possible it was used somewhere in similar country? is the flashguard protruding from bottom? similar bayonets could be used even in Weimar or in WW2 but this bayonet has no typical configuration for weimar era rework. Any old proofs visible on pommel, crossguard or ball finial? More detailed photos could help.
Ok do better not, when there is possibility anything to damage, flashguard is WW1 same as the scabbard, there is remains of imperial proof. Evidently the blueing on scabbard was done over cleaned rusting surface.So the blueing is not period, and could be done post WW2 from a english armorer to sample.