Regarding the casting call "Region" drop-down list when creating a new casting call, I find I have two difficulties:
It is unclear what is the consequence of choosing "Any" vs. one of the regions in the list. I'd like to suggest that some brief instructions are adding saying how those cases affects the visibility of your casting call when people searching for casting calls with various options.
The list of regions contains some names that are the same as the official names of English Regions, plus Northern Ireland and some subdivisions of Scotland and Wales. There are some peculiarities in the English regions, however, because "East of England" and "Yorkshire and the Humber" are missing, while an invented region called "East Anglia" has been added. I would advocate bringing your list in line with the genuine names of regions.
"Cit/yTown" also has an unguessable effect on searches, and I would advocate adding a brief instruction on the screen about this, too.