Does anyone know if your dynamic fluid runs low a light tells you on the dash.

The first you will know is when the red warning light comes on the dash, and logs a System Pressure fault

There is no level sensor/warning

As Mikey says, the red warning will come on the dash display advising to stop engine and to get the problem checked asap.

If you plan to top it up, then you need Land Rover cold climate power steering fluid at about £21 per litre on the auction site.

Mike