they're great, aren't they

, and I'd agree more likely to be salts than egg cups. They have similar rectangular lenses as the standard Lord/Jacobean style, though I've never seen aforesaid make with turned-over rims like these.
I remember Pamela Wessendorf saying in conversation some few years back that there had been other Continental makes with a similar lens-like surface pattern, and differentiating between the different makes was difficult, but I forget now who the other makers were.
Dating, based on appearance can be misleading - for example, the Czechosovakian Lord design was still being produced as recently as twenty years ago - the result of a very successful design, and perhaps even possible that Davidson knocked them out pre WW II.
If this was a Lord/Jacobean design we might remain in the dark since we don't have a comprehensive catalogue for all c. 275 different shapes etc.,
though it's possible that one of the catalogues that Pamela has posted might contain a bigger selection, and others here might have good information regarding Davidson's output.
Obviously they're pressed, so my comments about this shape not being possible for pressed glass were wrong.
Sorry can't help, but agree it was worth the journey - they may well be quite rare.