Have you searched for her death record? A county will issue a burial permit, and a death certificate would be recorded at both county and state
Since 1905 when a federal mandate in the United States required dual documentation (county and state) for birth and death and marriage / divorce, so her death certificate might contain that same information on her burial site. If she remarried after the death of her spouse, she'd likely be buried under the surname of that 2nd spouse, of course.
OOPS -- Of course none of the mandated practices of the United States will help, just realized all this was in England. But still there will be a death record, and likely a burial permit and the same principles still apply. The govt. of most nations like to keep track of such matters -- birth, death, marriage / divorce, burial.