GLEN, GET A LAWYER!
For a start, your letter MUST state In its first sentence “I refer to my previous correspondence “ - which statement automatically means You are including ALL of your previous correspondence with CASA in your discussion. Without those words your claim can be limited very quickly by a skilled lawyer. Please, please, get a senior commercial lawyer on your team otherwise you and your wife are going to be ambushed at your meeting and chopped up.
Furthermore, and sorry for being sexist, but unless your wife is a lawyer with an encyclopedic knowledge of the regulations she is going to be out of her depth. No good can come of this meeting unless you have an experienced lawyer with you who is fully conversant with your case. You are going to be facing an experienced and fully briefed team with all the facts at their fingertips. They may have rehearsed their responses ( I would). They will already have expert legal advice on their potential liability and a game plan to minimise it. You on the other hand, won’t.