After the work on the bilge was finished, we could install a new bilge pump, which is a fully automatic Rule LoPro 900S. It has an in-built water level switch, a flow-back preventer and it can be set to run on schedules too. We use it with the low setting which turns on the pump when the water level reaches 3.3cm.
The installation was very easy. It's connected directly to the battery with an appropriately sized fuse, all connections are done as high as possible (cabin floor level) and are heat shrinked.
The previous bilge pump was screwed down into the bilge floor, and now that we've laid brand new laminate there, I wanted to avoid using screws. So I fixed the pump with some drops of Sikaflex, which is strong enough but can be removed if needed.
We tested the pump with a bucket of water and were satisfied with the result.