Can I start group lessons any day of the week?

The group lessons that are for 3, 4 or 5 days start on Mondays, and the ones that are for 2 days start on Saturdays. It is not possible to start on another day of the week, except on 6 December, 27 December and 2 January, when there is a special start date for the classes that are for 3, 4 or 5 days.