Agree with Chris, those prices look great and it does get really taxing teaching more than 3. I often get one student to sing, and then the others can watch them for certain techniques, such as watching the belly for breathing or listening for breathiness.
(Glad to have you in the gang, Lily! I’m a singing & voice teacher in Guildford, moving to London in September! Hope the garden city of Leeds is working out for you!)