Both of these plants grew here for years, but they both left here years and years ago. The pictures I have are all older and not very good. The difference I notice is in the chalky eye/ band. On VICTORIAN DAYS, the eye has a noticeable "notch" in it and on NILE PLUM, there is no such notch. I don't know if you can see it from these not so good pictures but here goes. These pictures are over 10 years old, and all that I've kept of these two cultivars. The first one on the left is NP and the other two are VICTORIAN DAYS. Edge is also a bit more apparent on VD.
NILE PLUM and two pics of VICTORIAN DAYS.