As I understand it a big part of the case was that they went to France, where the age of consent is 15, and moreover I believe they lack the 'position of trust' laws prohibiting relationships between teachers/other similar figures and people aged 16 and 17. Hence why he is been charged with child abduction rather than a sexual offence.
I am not sure therefore that is appropriate to describe him as her victim, as he has not been convicted of any offence. I would imagine that his lawyers will be exploring the definition of child abduction and trying to define his behaviour as outside the scope of that.
One of the things in the paper at the time was that they reviewed similar relationships from the past. It was common that the relationships did appear to be abusive. But current laws do not necessarily define abuse and Forrest is not on trial for abuse.
E.g., if a 16-year-old male and an 40-year old male had a homosexual relationship in 1999, then that would have been criminal. In 2000, it was no longer criminal. That does not make either case a case of abuse, although in practice it might be.
Obviously she lacks a lot of legal protection in practice because her name, face, Facebook, pinterest, and numerous other things were (and remain) plastered all over the internet.
Hopefully everything will turn out ok in this case:
www.dailymail.co.uk/news/article-2340846/Police-search-missing-schoolgirl-Lorna-Vickerage-14-disappears-car-dealer-John-Bush-35.html
but in the internet age, her name, photo, etc. are effectively indelible.