I cannot stand Andrew., so arrogant and detached........BUT, in mitigation, it is alleged it happened in the UK, where the age of consent is 16. The text send by the accuser seems to suggest she was willing and indeed chuffed that she had 'slept' (what a euphemism...) with the Prince.
As for the trafficking element I doubt very much whether he would have been aware of that.....simply a close friend (ie JE) providing a good time for him.
Definitely not an extraditable offence.