Thank you, again, Jonathan. Your additional thoughts are very much appreciated.If some other kind forum member, with access to one of these publications, doesn't stumble across this thread, I shall put consulting them on my (growing) list of research tasks, for the next time I pass through London.(Although I haven't yet checked, I feel certain the British Library and/or Kew will have copies of the Directory (probably the BL) and the Civil List (probably at Kew).
I'm not surprised that IN ORIENTE PRIMUS has sold out. As a result, I suspect there are now likely many disappointed people!