Sooo.. Installed the new drivers, opened up the software and it was locked down at my right corner on my right hand screen.  After a bit of fiddling around (incl. doing a full DDU to remove any traces of old AMD drivers, which didn't help) it still persisted.  Finally able to pull and drag the window to my main screen.  But I can't seem to adjust the interface to a decent sized window.  So it either full screen, or this which is the smallest I seem to be able to make out of it.
Ohh swell ! Just started it up again and it is back to my right hand screen, in full screen mode.  If I click to restore the window down, it end up (after dragging it from the left hand side) spawning across all three monitors !  
 
Anyone else with multiple monitors that has similar problem ??  Would be grateful for any suggestions as to how to solve this !
Maybe 
@LtMatt have some suggestions ?? 
