Teaching assistant and pro rate wages

SWtable92

Hi my partner is a teaching assistant within a school and works part time hours every weekday. She is looking at applying to another school but is worried about whether she would owe money given that her wages are pro Rata and she hasn’t worked the full year. If she handed in her notice after having the summer holidays and potentially still being employed by them over October half term would they deduct from her last pay packet and how is it possible to work this out. I appreciate the information I have provided is fairly vague, if you need specifics then I can try provide them.