Update!!
Well - I started to realize after a bit of reading and finding that my latest read was not first on the kindle (sorted by newest read) - that it might have all been caused by my lack of updating to 5.3.3 and lack of wifi connection.
So... I updated to 5.3.3, re-applied the python and linkss updates, and had some snafu's for a bit - but it appears as though it's working now. Black background took, and latest book read also appears to have taken. Not sure if it's actually properly at 0.7N right now- as the info.txt shows 0.6N and previous attempt to remove it failed, so I fear I have a mixup of 0.7N and 0.6N somehow!

But, so far so good at the moment.