I've never seen Little Spotted, but judging from the book, your bird has too extensive an area of spotting on the back to be this species (i.e. it's a bigger bird, with more space for spots). I can't make out the detail in the face, as you seem to be able to do, but it looks fine for Nubian female to me. In any case, if it was taken in Samburu, that's way out of range for Little Spotted which according to the 2nd edition of Birds of East has one ssp (with barred underparts) in a very small area of SW Kenya, and another (with spotted underparts) in the southern half of coastal Kenya.