In answer to my own question, NO! Garage attempted to fit part today and unfortunately could not be programmed for a different car so I'm afraid a new part is needed. Thought I'd just let everyone knoe in case the same problem happens to your cars and to save you the time.
The GEM module contains a chip which is flashed when programming. When the GEM is new this is blank and is configured to your car. The module is then unique to your car and will not work on another model even if exactly the same type. The guy who tried it on my car was independant not Ford and he got everything to work except central locking and security systems.