I did a QXC not long ago, part of which was between Brentwood and Shoreham, and made damn sure I stayed to the east of Tonbridge and Tunbridge Wells so that I was not in danger of infringing London Airspace or Gatwick's CTR even if off course.
When you're inexperienced you should take every precaution not to infringe CTRs. I am sorry, but even student pilots shouldn't be that far off course.
Having said that, I'm not perfect and people make mistakes, so I hope the poor chap/chapette is not too dispirited and treats it as part of the learning process. At least nothing bad happened!
