From...

From https://www.slatergordon.com.au/class-actions/class-actions-101

How to start a class action

1. There must be seven or more persons with claims against the same defendant;
2. The group's claims must all be in respect of, or arise out of, the same, similar or related circumstances; and.
3. The group's claims must give rise to a substantial common issue of law or fact.

It is stated on this website that the lead, or representative plaintiff does incur risk.

However, I just spoke to a Client Services person at Slater & Gordon who said that this is not necessarily the case at all and that Slater & Gordon class actions are usually run on a no-win no-fee basis. On my broad description of the facts of the matter I was advised this sounds like a very good candidate for a class action.