Thanks guys, I will take all of that on board. The mother was fostered, and she was my partner's, brother's, mother. As you can imagine, the familial situation wasn't discussed much within the family. She lived out her life in Glasgow, she was married twice, had three children, and she died in 1979 in Glasgow.
I suspect that the address at 135 was a 'mothering' address. There are rumours that her mother got pregnant by the son of the family she was in service with, and talk of him not surviving the War. but that could just be too much time watching Downton Abbey.