The Waimakariri District Cemeteries CD produced by the Waimakariri Branch of NZSG does give details of areas, rows and plots for all 26 cemeteries in the district. It also contains outline cemetery plot plans. Users should double click on a name to see headstone transcriptions and burial records.
For James Groves the details are: Rangiora Lawn Cemetery, Area Left 2, Row 001, Plot 022. His headstone transcription is: "J. Groves 33353 Rfm Rifle Brigade, 1st NZEF, died 30 March 1957, aged 75 years.
For Eva Elizabeth the details are: Rangiora Lawn Cemetery, Area Left 2, Row 001, Plot 023. Her headstone transciption is: "Eva Elizabeth dearly loved wife of James Groves, died 19 December 1952, age 59 years. RIP. Eva's funeral was conducted by Fr Costigan.
Note that the records held by Waimakariri District Council give the surname as Groove.