I dont think there is a limit,
"All trainees must then complete 52 week’s of satisfactory supervised and assessed
training in employment and pass the Registration Examination for admission to the
register. There are staged assessments every 13 weeks. Trainees are eligible to sit the
Registration Examination after a satisfactory 39-week Progress report-3 and after
completing 45 weeks of training. There is a final assessment at 52 weeks and a final
declaration by the tutor, which must be satisfactory. Once the Registration Examination
has been passed, the 52 weeks (or more in some cases) of satisfactory training have
been completed and the other requirements met (such as providing a Health
Declaration), then applicants can be entered on the register."
Most candidates do it within a year but if your m8 wants 2 take a break, she probably can. Its best if she asks her university!