In message <HkkJb.5098$Gh2.45300923@news-text.cableinet.net>, Dom <domafp@blueyonder.co.uk> writes

If you create a file called "stop_after_send.txt" in the client's
directory, it will complete the current WU and then exit.

Ah, just the information I'm looking for.  Just a blank file with that title?

(I don't recall seeing you post on this NG before - however I doubt
that anyone will offer you chocolate, cats or alligators as a
welcome here ;-)

:-)  used to run SETI religiously, but got out of the habit.  It makes a lot more sense now that I can use network resources-- I'm a paranoid backer-upper, so legacy machines stay on the household network just for that purpose, and now at least they have something else to do.