The plot was noted as a "purchased" plot when first opened and on the following two burials.
There is a headstone, sadly now laid flat, that only mentions the GILBERTHORPE burials (copy of the photo is on its way to you)
I don't have the post 1946 burial book images yet, to check the last GUNNEE burial but the 1937 GUNNEE burial is noted as plot 10843 and it refers to it as a reopened "purchased" grave.
I wondered if you noticed there is another GILBERTHORPE grave just six plots away ?