When you book with TC do they ask for details of the person who owns the ST that qualifies, or just the name of the person travelling and using it ? I'm guaranteed but my brother is in the ballot with my uncles ST and his own, so obviously he has two chances but can't put a name down if they ask whose ticket he will be using, as that will depend on if either his or my uncles ballot application is a winner, if that makes sense.
TC seems the best way for us both to book, as we can both book on now, and it wont cost him anything if he doesn't get a ticket, just hope they don't ask for ST holders name who qualifies.