Re St Pancras
There seems to have been some Bowdlerization going on: this older BBC report confirms my memory of the rather abusive clearance. This may have happened in substantiation of HS1's removal of more bodies from the graveyard in 2001.
In 1859, Charles Dickens specifically mentioned it as the scene of grave-robbing in The Tale of Two Cities, and at that time, shortly before the arrival of the railway and after the renovation of the Old Church, it was not far off a wasteland. Other elements of the fabulation appear to be the suggestion the old church itself had been replaced, the original moved to Wanstead.