Unique Values in Drop Down
That seems to have worked though I will have to look at it more closely to understand what it is doing.
One other question - it feels like I am almost there!
How do I ask it to return only unique values in the drop down. You will see from my set up that the child drop down could return the same date three time. Selecting any of the three identical dates correctly shows the three available vets in the grandchild drop down but it would be neater to simply have one of the same date...