DD, The struggles you are having are common all over the world. Finding the next level of diagnostics and rehabilitation can be a challenge.

It sounds like you might need to look for a neuro rehabilitation hospital. They are not common so it might mean looking a distance from where you are.

Here is one but it appears it requires having supplemental health insurance.
Trauma rehabilitation :: The Victorian Rehabilitation Centre

[ Spinal cord injury

The Victorian Spinal Cord Service, located at Austin Health, is the primary service provider for people with a traumatic spinal cord injury.

Alfred Health is the other service provider predominantly focusing on non-traumatic spinal cord injury.

Patients with a spinal cord injury have complex high-care needs. The majority require access to specialist rehabilitation, equipment, home modifications and attendant care packages funded through an individual support package for long-term care needs.
Acquired brain injury

Acquired brain injury (ABI) encompasses a wide spectrum of brain injuries acquired from traumatic and non-traumatic causes such as road trauma, bashing, suicide attempts and strokes.

A small but significant group of patients with severe ABI's require specialist subacute services to meet their rehabilitation needs. These include intensive nursing and/or managing complex behavioural issues as well as specialist allied health services.

There are two services that care for people with moderate to severe ABI: Caulfield Hospital at Alfred Health and Royal Talbot Rehabilitation Centre at Austin Health. ]