In cases like yours where you are close to the official limit it is a good idea to email the medical group at the CAA with your prescription details and ask for their opinion re a first class.
The astigmatism correction is considered AIUI when assessing total refractive error and a large difference can indicate amblyopia (lazy eye).
You could ask for just a class 1 ophthalmic assessment at the Belgrano, and if that is OK continue with the rest later, at about the same overall cost.