Drive in the gate at the Blackrock (Northern) end of the cemetery (red arrow - above). Keep going till the road turns sharp left and follow it further about 50 yards to the first small passage on the left. You can identify this passage from the view below.

Go down this passage and take the fourth pathway left (below). The grave is shown in red.

The grave is on your left about 6 graves in and should be recognisable from the image (below).