Hi there Sara - I see you have already heard from my sister-in-law Victoria. However, as she does not have any further information, I will pick up the lead, Our paternal grandmother was indeed Alice Rainbow. (She married a Sydney Rabbetts). Her mother was however, Amelia Kate HENDRA. Her Father was Herbert Samuel RAINBOW. I will call my cousin Martyne who has some extensive research on the Rainbows. Either Martyne or myself will get in touch and confirm Herbert Rainbow's siblings and parents, and hopefully we can go from there and track down your Alice.
Cheers & best regards