Most students have to learn French or Spanish in school even though that not very many people will need it in there life but the likelihood is that life in UK you will come into contact more deaf people than French or Spanish and communicating with deaf people if helpful and you could reach out to more people. And yes, you can also reach out to more people if you learn foreign languages too but if you are willing to bring your business / life too different countries then you can take a class on them languages but not many people are planning to do that. Im not necessarily saying get rid of French / Spanish but it would be helpful if students learned sign language once or twice a week and it will also add to there knowledge and a new thing to put on their CV in later years.