OK, a little more info. I attempted to restore just the data from the October nandroid and it failed. In TWRP, when I select Restore, and select the October nandroid, I am presented the choice of restoring Data and/or Boot. I've tried both now and both end in error. I get the following text on the tablet.
Restoring data...
E: extractTarFork() process ended with ERROR=255
Found this thread over at xda on the error message. https://forum.xda-developers.com/nex...or255-t3302462 Maybe it will give me the key