First you will need to create a Dynamic Group in the Data Digger for Pupil Premium students. See - Using Data Digger for creating a Dynamic Group or Static Group of students
Head to Reporting > Data Digger, and enter Pupil Premium in the first dropdown box.
Click on the number in the blue circle and give this Group a name as you create the Dynamic Group.
Then use your Incidents report and and select Pupil Premium from the Group dropdown.