Another grave plot conundrum Travis. Roberts headstone is in the churchyard so one would assume that this would be the resting place of his mother as well. I recognise the location of this from the CWGC headstone of Pte J Norcross which is just behind.
The entry in the register for 597 I believe is just the number in the register and not a plot number. The churchyard plots are organised on an Alpha numerical grid system. The notes in the margins in the register don't seem to allude to row and plot numbers though. In my notes, I only have a few recorded with actual section and grave numbers for cross reference. I know where A, P, Q and V sections are with their corresponding grave numbers.
I have no record of Clara's husband being recorded in the churchyard, he does not have a CWGC headstone and I have not seen any commemoration on a family plot. That is not to say that this does not exist though. When I distribute the remembrance crosses each year I tend to loose some and gain the odd name each year. I assume Robert will actually be buried close to where he fell.
Without an actual plot number it will be difficult to find Clara. Most of the plots for CWGC headstones from WWI are in the first section immediately through the gate. Again, an assumption, Clara should be somewhere around that area as that would be the area in use at the time but unfortunately there are a lot of laid down headstones there also.
I will make a note in my records to keep an eye out for her when I am distributing this year.