Hi as far as I know it is part of JY/TS' terms and conditions that once the price is confirmed when you book, you will not be subject to any surcharges - Monty correct me if I have that wrong!
Looking forward to the update on various questions very soon as the balance is due today. As I have it automatically debited from my credit card, I got a notification email from JY this morning to say that it has been processed. So I am definitely going (bar any catastrophes!!).
Cheers,
Bob