Thought this may interest you. The school and individuals involved may be up for some serious consequences if the WWC law is not followed. We were warned at work that we must have our card on us at all times as if there was an inspection or audit, we may be fined ourselves and the organisation may face penalties.

ORGANISATION PENALTIES
If a Working with Children (WWC) Check is required, you must not engage, or continue to engage, a person in ‘child-related work’ if the person does not have a current Assessment Notice. This does not apply to employees or volunteers who have validly applied for a WWC Check and the application has not been finally decided or to employees or volunteers who are exempt under the Working with Children Act 2005.
Penalty: Natural person: two years imprisonment, a fine of 240 penalty units* or both

As an agency, you must not offer the services of a person to undertake ‘child-related work’ if the person does not have a current Assessment Notice if one is required. This does not apply to people who have applied for a WWC Check and the application has not been finally decided or to people who are exempt under the Working with Children Act 2005.
Penalty: Natural person: two years imprisonment, a fine of 240 penalty units* or both

INDIVIDUALS
If you do not hold a current assessment notice, you must not undertake 'child-related work' unless:
- you are exempt under the Act
or
- your child-related occupational field has not yet been phased in or
- you have applied for a WWC Check and your application has not been finally decided.
Penalty:Two years imprisonment, a fine of 240 penalty units, or both

I didn't track down the info on 'penalty units' but I understand that it amounts to about a $12,000 fine. OUCH.
Given the application fee is only $77, I think it'd be well worth them getting it done.

As for experience and qualification... well, I think that comes down to the individual. Yes, of course training can be extremely useful, but I've come across some highly qualified aides and therapists that just don't 'get' the child or the needs of the situation, and some unqualified individuals that were just born to it, and were BRILLIANT.

Sounds like a tricky situation. All the best.