Hello, and sorry for my tardy response.
I have now tried the "long wait" with the restore. I left it for 12 hours initially, but when I returned to it the machine wouldn't respond to my mouse/keyboard inputs, so I left it for a further 12 hours and it's now responding but there's no sign of any restored data.
When I "went back" I was in Time Machine. I opened the contacts application to the card I wanted to restore and then Entered Time Machine and scrolled back through the dates I had backed up (about once a month), all cards were blank.
Are you saying that I have to restore the whole of my contacts database?