the monitor is fine and works without problem with any other atari ST i plug in so this tells me the screen is fine
the lines are solid and do not move in any way whatsoever
i use an ST/VGA adaptor but it is fine on any other ST i use so believe that to be ok
what i was going to do was maybe make a scart lead and try it in low/medium res and see if the lines are still there? if they go it could be just the high res mode, if they stay then it's a permanent feature i guess!
they lines aren't caused by any interferance as i use other ST's on the same desk
i'm going to have another closer look at the monitor port :0)