Sounds odd - the reach/overhang of the cable pinch bolt doesn't differ much between front derailleurs for double/chset, and presumably your Orange had something like 105 derailleurs back in '94 which is the same as Ultegra ?
Can the cable guide be removed from under the BB ? Sometimes they're bolted on. If so, you could remove it and try drilling a new hole off to one side, and refit it. This could be a way of centering the front gear cable a bit (I'm assuming it's rubbing against the drive-side chainstay ?) as long as it doesn't then put the rear gear cable too close to the tyre.
Willi Moore Tourer 531c / Record (~1985) | Dawes Edge XT (1994)
MBK SuperPro (2002) | Dave Hinde Airplane (2003)
Reise Und Muller Birdy (2007) | Cove Stiffee (2009)
Dawes Jackal (1988) - Sold | Kona Explosif (1989) - Stolen
Dawes Stratos (1991) -Sold | GIOS Compact Pro (1993) - Sold
Trek 8500 (2001) - Sold