I have checked my tickets on the Etihad web site and found:
1- 1 ticket re-issued 9 August 16 due to schedule change
2- 1 ticket issued in March 16 with no changes
3- 1 ticket re-issued 20 Oct 16 due to schedule change
I expect that I now won't get a car for (3) but am hopeful for (1) and (2) based on this thread.