Proof of sorts that some programming is still being stored as off air copies on the iPlayer and that recording re-used on repeated transmission.
The Art of Gothic from 2014 is being re-run on BBC FOUR currently. and low and behold the iPlayer version that's available for at least EP1 has the 'HD' element visible on the DOG
For reasons best known to the iPlayer sometimes the programmes that appear on it are broadcast recordings with DOGs, ECPs
and what not, and other times they're "clean" as if they've come from the server files.
For programmes that go out live, to record them as broadcast is understandable. For other programmes though, it's anybody's guess as to whether it's clean or off-air . I suppose its a matter of whichever is quickest to get it on the iPlayer. Not that it really matters as the programme is the main thing.