Collation both fields is SQL_Latin1_General_CP1_CI_AS, and yes, you'd (generally) get an error on mismatch
> It's sounding like it's one of those situations where the difference is so blindingly obvious that you can't see it for the glare, or ridiculously pernickety.
Yeerrrz - I've already tried explaining it to the cat, for the DOH! moment.