Thanks for the replies; the car however, let me know quite quickly that the connection was incorrect after a brief test start. When I checked the Diagnostic Module, the car reported that the data received was "implausible", and the vehicle was in "limp home mode"; so I returned the valve to it's original orientation and have had no further problems. On the bright side, the EGR valve now functions normally, and the check engine light has been OFF since I replaced the vacuum tubing.
Thanks
94 E320