I recently visited a cemetery (not in F o D but the same could apply there) where a whole row of graves, I found, had been taken out 20 years ago when trees had been planted and the driveway widened. I was there because one of them was my great, great, great grandparents' grave and I had told a relative in Canada that I would photograph it for her. When asked what had happened to the inscribed stones no one knew and there was no sign that they had put them anywhere else in the cemetery though there was ample room for them!!! However someone had previously transcribed the gravestones so I managed to get the transcription. I don't know how the council felt it had a right to get rid of the stones as there would have been no problem in repositioning them. In this case the next row of graves has the stone of my great, great, grandparents and the grave of their son, my great, grandfather is close by too. So what they had effectively done was to have erased all records of a whole row of grave stones and with it a generation of my family's records! The cemetery had been established in the mid-1800s and the stones were put there relatively early within a decade or two of the cemetery being established.
This removal of graves and reuse of them shouldn't be allowed. Cemeteries also form havens for flora and fauna in built up areas and should also be valued for this. We are not so short of space as to jump into each others' graves!