I tried all those because I thought she might have been Elizabeth too because that is also shortened to Bella especially since the rest of the family have such Scottish names. But after checking around she was defiantly born under the name Bella and nothing else.
You may be able to help me with another name though, I was never able to meet Bella but I meet her sister regularly on trips to Glasgow I only ever know her as Nan. Apparently so did everyone else and know one else knows what it could have been short for, do you know what it could have been?
I have been considering a trip to Edinburgh to look further, is it free to gain access to their records when you visit?