Would someone be able to confirm that the edition on the syllabus (Zimmerman) is essentially the same as the Chester edition (which, in turn, is the same as the same as the Kohler studies in Melodious & Progressive Studies -Cavally) ie it is the study entitled "adagio patetico"?

Also in bars 3 and 19, the 2nd turn in those bars is from a D (quaver) - am I correct to assume that the last D of the turn becomes the D dotted semi-quaver as written immediately after the turn- ie the last D of the turn is not repeated for the D dotted semi-quaver?

Yes.
The old Zimmermann edition is the same as the Chester edition (haven't got the cavally so can't respond to that bit of your question) my students regularly choose to learn this study. We always perform the turns as you describe. Good choice!

Thanks for the reply- pleased to know that I was interpreting the turn correctly. Have you taught/used the Weber "Romanza Siciliana" for Trinity grade 8 - how flexible is the timing of the cadenza do you think?