1990 Vanden Plas Passenger Side Door Won't Open
 

Front passenger side door won't open from the outside. Electric door lock and inner door handle works.

Is the car in question (and what IS the question? ) a 1990 xj40 car or a 1990 Series III V12 Vanden Plas (Canadian market).? The door locks are quite different. The lock mechanism in the photos does not look like a Series III lock to me.
The xj40 did have door handle (exterior) problems and the solution was replacement of the handle mechanism. But if the car is an xj40 then you will get a better answer on that forum.

1990 XJ6 Vanden Plas, Front passenger side door can be opened from inside but not outside. Threaded rod from outer door handle appears bent and just slips in and out of whatever (?) it's connected to (can't really see.)

Your car is known by the factory code xj40, and there is a separate forum for that model. But it sounds like you have the problem I mentioned: the outside handle failure. The handles were redesigned internally, I believe, to correct this issue but if you present this to the xj40 forum you'll get a better response.