It may be that it was retained by the exam board for standardisation. In Music, on training days, we often have to mark past students' work as part of the process so we understand how the mark scheme works, and hopefully so our marks don't get moved during moderation.
In my school, we did things differently from others in terms of KS3, GCSE and A level (no longer the case now). As a result, my DDs started A levels in year 11. Older DD was studying English but the specs for the new A levels had not been released when she started the course. The exam board asked the school to trial some work and DD's group wrote an essay on a book. They were sent off to the exam board to be marked. When they came back, they asked the school to get DD's permission to send them back a copy because it was really good and they wanted to use it as evidence of the highest mark band. She was very flattered and agreed. I suppose it could well be out there now. Was yours anonymised OP?