Thanks Baltic,
I think I see now. Your standard set up was exactly as ours is, and you've simply fed the water from the chrome waste fitting in the shower to the sump/pump unit so that the water self-drains and pumps. What confused me was that in the photo you posted of the sump, it looked like the entire shower floor had been made into a grate/drain, due to the mesh like matting and what appeared to be a circular wooden grate beneath it, but perhaps that's just the finish of the heads compartment floor of an 06 model, as opposed to ours which is just a white non-slip finish applied to the GRP.
Nice mod. Saves standing in the collecting water, having to pump it manually, and then keep going back and running the pump repeatedly as the remnants of water collect in the standard drain with nowhere to go.