We've had a number of instances of parents being unlinked from their children within the Parent Portal, which we only ever find out when the parents contact us.
Recently, a few days before A-Level results, we had a similar issue with a few Student Portal accounts (see ticket 764704).
Please add some form of audit trail so that we can identify unlinked parent and student portal accounts quickly. This is something we'd need to do for parents ahead of reports going home, or asking parents to verify information. Similarly for pupils, it's something we'd need to do before releasing exam timetables and exam results.
