Females and non-breeding male Bishops and Widows are notoriously difficult
to identify. The main problem is that the features which separate them is
not constant, and size, etc becomes important. Usually we identify them by
looking for a breeding male, and otherwise we ignore them.
Based on the streaking which is limited to the breast, and the fairly
slender bill (compared to the next one) I would say this is a female
Whitewinged Widow.