Hi Stuart
I've got one pump in the tank on my van and one in the IBC in my garage.
During the winter I empty the water from the tank on the van back into the IBC in the garage (to prevent freezing). On my van tank it is very difficult to squeeze the pump and the connected hose through the hole in the tank and a pain to keep disconnecting the hose, so I have just left the pump in the tank connected to the hose. It only takes a couple if minutes to empty any remaining water.
Steve