Actually, I think this is the curse of metric again. The word "metres" seems to have the effect of switching off that part of the brain that records measurement, so that numbers become totally meaningless. Or perhaps it was because the skeleton had its feet missing, so they had to replace them with metres.
Interestingly, the Mail also runs a piece by the same author (Damien Gayle) about finding signs of life buried beneath the West Antarctic ice sheet. The depth is put at "HALF A MILE" (in caps), and is instantly recognisable.
If the other story had had Richard III buried half a mile deep (close), Gayle would instantly have seen it to have been nonsense. And, amusingly, in the Antarctic piece, he talks about water being blasted in at "fifty gallons a minute" – equivalent to 800 glasses of water. Clearly, he needs to be sent to a re-education camp.