Just as a tip for anyone who does searches like this:
I have found it helpful in some cases, especially where a person is NOT dead, to add search terms for where a person lives or lived. For example, in this case I included "Heathfield", but still found nothing.
It sometimes helps, though, because it might lead to a local newspaper mention of the person celebrating 100th birthday, or some other event, or to a Facebook or other social media post.
I also searched her children's names, in case that hepled, but found nothing.