Thanks sudokulover (and K). That was the "tipping" point.
Rather clever orientation of the unclued lights. The vessels go across, as the subject matter goes down to the 48A! Haven't got 22A yet.
Ixion: 1D - K from Wiki.
28A thought "toxic" meant "leer", but need the X for the quotation. ??
46A - I just went with the obvious horses. Can't quite fit the carriages.