Hi Ken,
I have been puzzling over this in the garden, armed with Bradford's Crossword Key Dictionary,
my Seiko Britannica [electronic word solver] and a copy of Chambers and I still can't help you!
You have probably examined the possibilities of 'seam' being 'ore' and 'ace' being 'expert' and drawn a blank like me.
Where is Jerry when you need him?
Kind regards,
Caravaggio