Earliest date that has empty cell next to it, from list of dates

Hi
I have a table of tasks with due dates in a column and a column which indicates if tasks are complete. I have a cell above the table which should display the earliest due date of incomplete tasks - that is the cell (d1) I would like a formula for. I would like to meet the requirement without having a formula that must be copied down in an additional column in the table.

Notes:
If a task is complete it will have "y" in the "Complete?" column and if it is incomplete there will be nothing in the "Complete?" column.
The list of tasks may be long or short and will change regularly.
The tasks are not necessarily sorted according to due date.
Not all of the tasks have due dates.

I have an example below showing the desired result. Thanks for any assistance.
Capture.PNG

Sorry for off-topic interjection:

Although there is no official rule regarding this behaviour, we request that wherever possible both the question AND the answer be provided in substantive detail here within the thread. An attached workbook is an excellent aid for posing a question and offering a solution, but solely doing that with no in thread explanation makes it difficult for researchers to understand or consider the Q & A of this thread without downloading what may be a pointless doc to them, if they can do that at all. Doing that also hides the content from search engines so others may never benefit from this.

I'm sure you understand, and we look forward to seeing you post your formulas/macros in your posts for the searching benefit of all.

Thanks again for all your hard work here!