Ian,
I'm a newbie to Photo Mechanic.
I've been reading through the User Manual and my IPTC Stationary Pad form layout is completely different to that in the Manual. I don't seem to have fields for the 'photographer' or 'keywords' and the like.
There are two sets of IPTC dialogs: the new scrolling/resizable ones, and the original 'classic' IPTC dialogs. There is a setting in the IPTC/XMP tab of the Preferences dialog that controls which set of dialogs you'll see. It is a checkbox titled "Use Classic IPTC dialogs".
But both sets of dialogs have the Photographer and Keywords fields. They're just in different places. It may be that you just need to scroll the fields up or down in order to see them, or just resize the window larger.
HTH,
-Kirk