Catherine
I've attached a PDF of all of the Conroy Burial Records between 1862 and 1962. You don't give any dates for the burials for which you are searching; I assume, from the Christian names you gave, that the appropriate record numbers would be 18113 and 26285 each of which shows a burial in plot 442, Section 16. I've transcribed all of the headstones in Section 16 and there is, unfortunately, no extant headstone on this plot. My Grandparents' headstone, which is in the same section, has also virtually vanished due to the depredations of weathering and mechanised grass cutting. The numbers shown in square brackets in the remarks column are the sequential numbers in the original Burial Register kept by Derwentside Council; if you quote these they can easily find, locate, and mark the appropriate plot.
I've also attached a JPEG showing the layout of the north graveyard if you wish to visit it. It is taken from the information board on the wall at the Durham Road entrance to the graveyard. There used to be a pedestrian entrance at the north end of Section 19. This would tie in with your grandmother's recollection. However, Derwentside Council (as was) totally renewed this fence several years ago and, in their wisdom, decided not to re-instate this pedestrian access, so the only access now is from the Durham Road end.
Good luck with your researches.
PatB.