FWIW, the Pantera wiper motor is a Lucas item, and contrary to rumor, is the only Lucas wiper motor on the car (the fans and window motors have sometimes been erroneously labelled as such. )
The Pantera wiper motor is common to about a zillion British cars--Jaguar, Hillman, etc. etc. so they are readily available in junkyards that cater to those beasts, if yours is truly shot.
I'm not even close to being smart enough to understand the intricacies of the Pantera wiring diagram, but any guy with electrical knowledge will be able to analyze the diagram and determine which pin on the motor receives power, ground, etc.
(As an aside, the wiper spray bottle, pump and bracket are also straight out of a Jaguar....)
Mike