Kirsty, you seem to be failing to grasp that we "KNOW" nothing.
Until you get certificates, or other records, it's all conjecture.
I urge you to start looking on freebmd for early deaths if the names of your mother's maternal aunts and uncles seem unfamiliar. (ie these are siblings of your mother's mother)
There is also the possibility that the family called them by another (pet) name, so don't jump to conclusions