Why did you only join "this new sixth form" one month into the academic year, which caused this situation in the first place? What happened at your previous sixth form?
How have you "missed out on a week's worth of teaching"? Is this in addition to the one month you lost at the start of the academic year (due to joining this sixth form late)?
You say that "Probation is practically when you are given a certain amount of time ... to be able to catch up with the work, assignments, attendance ETC." How can you catch-up attendance? If you started with this sixth form on an attendance of minus one month, due to starting late, how can you ever get that number back to where it should be? Were you expected to make-up the time by attending on weekends, or in the evenings?
Or do you mean that you were given a target for attendance since starting (say, 95%) and didn't manage to reach that target? If so, why was that?
How many assignments did you need to catch-up on? How many did you manage to catch-up on?
Did the sixth form put any measures in place to help you catch up? Or were supposed to just handle this yourself?