From what I've heard - and this could well have changed or be out dated or incorrect, but it was:
Full dress for CEO, CO and RC level only - this included Tunic and hat (expensive for 1 or 2 wears)
Formal uniform - same as what staff wear - khaki pants and shirt with broad brimmed hat
Field Uniform - NOT PPE, but hard wearing uniform for use in training where PPE isn't needed, for staging area people and in areas where PPE isn't required, undertaking pre-planning, risk assessments and field inspections - again driven by staff as the khaki isn't appropriate
PPE - Operational (full suite from L1 to L3 garments and associated items)
Casual - 'Approved" CFS casual wear - i.e. approved has logo (star), non approved taxi sign
VFBA may have more info as they had several people on the uniform review committee!