thought i'd have another bash at this. so downloaded a qtlockscreen.ini with images, re-installed qtlockscreen rebooted, replaced ini and set images in correct dir. killall qtlockscreen.

i locked the screen and pressed power button and there it was the original messed up lockscreen. going to re-install but this time rather than purge i'm going to manually delete the lockscreen.ini.

done the above and got a lockscreen that worked so changed the ini file rebooted and still got the same lockscreen.