Don't know what the rules are in the UK and elsewhere but down this way (Aus/NZ) detachable mains cables need their own label which specifies not only test/next test date but the asset number of the device with which the cable was tested, that way you know where the test results are for earth resistance etc should the cable be moved to a different device, as often happens, and that device were to be involved in an incident.
Fixed mains cables do not require a separate label but we often do anyway out of habit as much as anything.
Sounds sensible to me (apart from the un-fused plugs, of course).
Does AS/NZ 3551 call for this?
Is this (labeling of mains cables) common practice anywhere else in the world, I wonder?
On the other hand (see post #21330):-
It took 2 minutes to test a lead, 6 minutes to label it up!