For someone who writes broken macros all the time, this was straightforward, what with all the practise...
The next problem was a missing field:
This is due to the fact that the fields "Open Date" and "Closed Date" had been converted and then re-named to "Open_Date" and "Closed_Date":
I simply dropped the underscore for these fields.
The next was another unknown field:
This was simply due to a missing bracket when denoting the column name:
I amended this to include the bracket after "[Close Date"
The next problem was there were no records being returned. This is because the date conversion tool was looking for the incorrect date format on the incoming field:
I changed the format to Month dd, yyyy which now matches the incoming date on both fields.