Just to add more to the story today...

I managed to gain access to the control box. With the control set plugged directly into the control box, and the USB key plugged directly rather than through the extension cable I was unable to get the unit, the control set, or the remote LED to indicate that it had any form of life.

I plugged the BT module back into the control box, powered on the car and all the module would do was flash the green light and click while the app made the same sound as in the video from the original post.

Is the control box defective?