Thank you very much for chiming in with the feedback on 15.1, Sluggo! Much appreciated
*edit**
Oh... just to mention, I don't have a Software Update item in my system preferences... under El Capitan... mine shows up in the App Store. I've always gotten everything that way for this OS and it's always worked fine except for the last security update that for some reason went badly, on restart as instructed I got a kernel panic and again on every attempt to restart. I was forced to boot into recovery mode and restore the whole thing from Time Machine. Never had the nerve to try it again until a few days ago I tried it booted from a clone and was able to do the update there so "fingers crossed" I should be able to get it to work on the MBP now as well.