Updated the model mappers to include the pre-value value which is now wired up to the display, now just need to get the data type's persisting.

src/Umbraco.Web.UI.Client/src/views/datatype/datatype.edit.controller.js

@@ -33,6 +33,7 @@ function DataTypeEditController($scope, $routeParams, $location, dataTypeResourc
                 description: preVals[i].description,
                 label: preVals[i].label,
                 view: preVals[i].view,
+                value: preVals[i].value
             });
         }
     }

src/Umbraco.Web.UI.Client/src/views/prevalueeditors/requiredfield.html

@@ -4,4 +4,5 @@
         required />
 
     <span class="help-inline" val-msg-for="requiredField" val-toggle-msg="required">Required</span>
+    
 </div>