Thanks very much Margaret.
We're planning a trip to the town of her birth to see what we can find out. Unfortunately, I know from the register that nobody is looking for me. As it's a bit sensitive we've decided to keep my Ancestry tree private for the moment.
We've also ordered my maternal Grandmother's birth certificate so we'll see where that takes us too.
All very frustrating at the moment, but I'll keep digging!
Thanks again.