Seems to have been something to do with the dictionary. It seemed to freeze if selected direct. Eventually the text typed would appear. It also seemed to freeze selecting American ( I reset in the end) and then going back to British.
However after doing a few look-ups on the British one it then seemed fine. Now in a book the highlight works and the dictionary appears (with "not found" if a sentence is selected). Seems odd.
Davidfor thinks it is being recognised as a PRS-T1 in Calibre and it's just the PRS-T1 notes plugin is now incompatible with Calibre. Unfortunately.
The first line paragraph indent seems a little larger than the other ePub readers, that seemed so for my PRS350 too.
Battery does seem good.