Thank you for the thoughts and info!
Unfortunately, my dead pixels are white and blue, with two red ones sometimes appear as well. I can't see them in normal use but yes, they get really annoying with dark screens. I might give Sharp a call tonight and see what they say (thanks saakmotu!)
Just so you know: With the two that sometimes appear in mind, i thought i'd try a complete battery removal and switched the backup battery to off as well, to see if this "cleared" them all. Of course, i really knew it wouldn't but i wasn't prepared for my Z not coming back on! Eek! Panic really starts to set in at that stage ;) Fortunately, if you look in the troubleshooting section of the manual, it says to remove the battery for 5 seconds (i did it for 15s) and do the restart sequence (pwr+rec+reset) and that brought it back to life. There were a few scary minutes there, though, where i thought i'd killed it!
@Tehas - Have you done anything about the rotation of your screen or just left it as it is? Not that i know if its user-adjustable, except maybe with a screwdriver and a steady hand.
Thanks again :)