Simple Pump control with Level Sensor

This should be easy, but somehow I'm finding it impossible!

So, Attached to my Profilux 4 I have an AC (uncontrollable) pump on powerbar 6E socket 4 and a Float Level Sensor at position 7, I want the powerbar socket to switch off if the water level rises and the Level Sensor detects it. Ideally, I'd prefer the start-up of the powerbar switch to be a Maintenance function, but it's the stopping that's most important.

It's not an ATO or leakage situation, and once the level is reached there's no need for an alarm (so I can't use Leakage detection), but if it could be Maintenance function stopping that before it timed out would be neat but not essential. I can probably work in some PL if that's the case.

Return Pump functionality looks a good option from the Resource Manual, but the videos give no guidance on using it as a stand-alone function - it gets combined with leakage, feed, maintenance etc. which is unhelpful.

If I try assigning Fill Water and 7 to S4 and Return Pump mode to Level Sensor 7 as a simple test, the sensor fails to have any impact on the socket state (I can move the float and see the sensor state changing so the sensor is fine, equally I can manually switch socket 4 on and off, so the issue is somewhere in the functions / logic).

Is this as hard as I'm making out?

Sorry I'm a bit thick but thanks to anyone who can help me out!

Mark