Where you where standing was the old coal fired power station and this is where the barges brought the coal in. It closed in the eighties and unlike the Bromborough power station i think this one ran into the national grid.
As Pace said - the coaling wharf for the CEGB Power station. When the place was operational, I remember it having a crane on it that had a grab which would be lowered into the boats on the river. Usually with mounds of coal on it too. A modern picture here (I take it this is what you saw on your walk): Clicky
This is an aerial view of the power station in the late 60s/early 70s - the two chimney stacks of the power station itself can be seen smoking away, and the wharf is top right:
Sitting on a cornflake, waiting for the van to come.
We saw an old electricity box there, so figured there must have been some sort of crane, we just couldn't figure out what for! It's a shame to see it sat there not doing anything now tho.