LBS Makes a Bo Bo

[PaulSecteur]

If you have a look at the rear of the parallel mechanism on the rear derailier you should be able to see the part number (at least its there with road bikes)

 

[gwhite]

I can conform this, the rear mech seems to be working the opposite way.

There is no way the lever can be responsible for this as the upward gear shift pulls the cable and holds it in the new position by means of a ratchet and pawl. It would appear that the rear der has been changed to a "Rapid rise" which would give the symptoms you describe.