The Uni and Egret both have a 4 pin input connector, but only requires 3 wires for input. This is done to allow different options to be selected by varying the input wiring. The standard controllers suits a standard 10K pot.
Simplest wiring is shown in the diagram above, left.
With this fitted, you can leave the pot set to whatever speed you wish and stop the machine with the switch. Fit it in series with the top of the pot, above, right. With this off, the pot also draws no current. So - wire the top of the Magura throttle to the top pin of the connector, leaving the second pin empty. A battery condition indicator can simply be wired between the top pin and the green wire to the pot.