Door won't latch on my '62 Valiant

I would really appreciate some more help with my '62 Valiant. The passenger side door has started refusing to close.:sad6:

It doesn't latch all the way, and it is difficult to re-open. The latch seems like it is not engaging properly when you close the door, and then hangs up and doesn't want to let you re-open it.

It would really help me if anybody could tell me whether this seems to be due to the latch itself, the striker adjustment or the hinge adjustment, then I'd at least know how to get started fixing it.

Thanks a lot.