TTS for Android Auto

I recently experienced android auto stopped having the tts voice going through its speakers with no change to my set up. I tested this with both my phone and my wifes (both working previously) in both cars. While looking into the cause (and I have still not found a solution as I am not using alarm stream etc) I came across a post from about a year ago which used VLC as a receiver. Text To Speech on Android Auto - #12 by lbandi2
This looked like a more promising solution however I am struggling with the api. I have had a base connection to my instance using a token to myurl/api that shows I have a working api and token however I am not having any luck with the /api/tts_get_url endpoint. When I went into the documentation while I can see documentation via direct link, on the following page of the api I cannot see it listed
REST API | Home Assistant Developer Docs
Is anyone still using it and can provide a basic script to demonstrate it using nabu casa and piper? Thanks in advance to anyone who can help.

Added I am currently receiving a 405 error

Added the 405 was likely to me just doing the test to the api via browser since it is GET rather than POST. the curl is resulting in a 500 internal server error

My curl command is below:

curl -X POST -H “Authorization: Bearer mykeyhere” -H “Content-Type: application/json” -d ‘{“message”: “Hello”, “engine_id”: “google_cloud”}’ “http://10.2.0.1:8123/api/tts_get_url

so I replaced the “google_cloud” call with “cloud” which seems to access nabu casa and seems to be working in a basic format.