There are 2 ways that this can be achieved.
1. The first is to use Bulk Data Deletion in Admin > Students.
This allows you to you delete in bulk student data in relation to Nationality, Country of Birth and Proficiency in English (PIE). Select the year or form and whether it is a current, former or future student you are wishing to remove the data from.
From the list select which student(s) you wish to delete the data for either individually or 'Check All'. Then choose which of the data items you wish to delete at the bottom.
2. The second is to use the Group Updater function in Admin > Students.
In this area, once you have selected the Year/Form choose the attribute you wish to update (Nationality, Country of Birth and Proficiency in English (PIE)). Once selected you will then have the option to select from the second drop down 'Not Collected'.
Place a tick against the students whose data you wish to update (either individually or 'Check All') and then update students at the bottom of the table.