It's a classic
There are three universities that offer a PGCE in classics; two in England and one in Scotland. Full details can be found by using the course search at www.gttr.ac.uk. Some state schools teach Latin, and we have noted 27 vacancies since last September. However, there are likely to be more posts within the independent sector. It is difficult to create a career just out of teaching classics, and you might find a second string to your bow would be useful if you don't envisage spending your teaching career doing the same sort of teaching. There is unlikely to be a department to lead and you'll probably find you are the only teacher, so there'll be few chances for discussing the subject with a colleague.