Oh dear, I'm sorry that the grandson won't be able to visit her final resting place. I did suggest at Reply#17 that she may have been cremated.
I assume that you had a reply from the clerk at Burnham then? I take it no mention was made of her name being in a memorial book or book of remembrance?
Well at least the grandson is clear about what happened to her even if it wasn't the desired result.
I'm afraid family history doesn't always give the solution that you would like. Hopefully though, the grandson has gained information that he wouldn't have otherwise known.