Thanks for the reply shruggy.
Ive been starting mc from a konsole terminal window after first becoming root with su.
Ive discovered that if I use an xterm terminal instead of konsole and follow the above procedure the the mouse works just the same as being a user
my DE is kde .. Ive found the desktop entry in the menu but it runs mc using konsole. Ive created a desktop icon which opens xterm as root, so I'll use that when I want a root mc.
sudo mc opens mc in a konsole window btw.