I'm sorry, as is so often the case in life after one asks a question that
has bewildered one for ages, light suddenly dawns. Thanks John for your
suggestion but my census dates and ages thing turned out almost certainly to
be a consequence of entering things my own way before discovering Gedcom
It probably warrants explanation. As John says, look in the Dialog box for a
census date in the All tab; the events tab will show the same date. The age
as given in the census is likewise mirrored in the All tab and Events tab.
Both date and age can be entered or changed in either tab or in the Records
window, although Gedcom Census takes care of all that for you if you use it.
The Objects tab in the Dialog is quite different because that date ( or its
absence ) is the one given in the date box on the Main tab of the Multimedia
item properties which is the only place where edits seem to be possible. Any
age shown in the objects tab is automatically calculated from the date
entered in Properties. Because I haven't ever entered dates for any other
multimedia and because it was just the Objects tab where this information
didn't always show, it took a long time but the penny eventually dropped.
Of course wading through the instructions would probably have produced the
answer - or better still, I can recommend using Gedcom Census from Day 1.