Surely this could have been checked by anyone with a £50 handheld GPS, or even an iPhone, rather than a low flyby in an airliner full of passengers?
The above shows a rather large gap in understanding of approach calibration requirements. Clu4U, it cannot be done legally or properly with a "handheld GPS or iPhone". Using such equipment is far worse than not doing it at all.
If on the previous flight it was noticed that the runway had shifted, there should have been a proceedure in place to update.
Having a "procedure in place" and having the required certified equipment in place are two VERY different things. And without the latter, the former cannot be done. And the latter simply does not exist in Antarctica.