If. you were to buy an ultra flow pump, it would not connect to the caravan because the plugs are different. You could disassemble the the Ultraflow pump from its hose and plug and then reconnect it to your old hose and plug, but that is a rather expensive way to do it and a waste of of the ultraflow pipe and connector, Its more cost effective to find another submersible pump and use it to replace your old faulty pump.
There may be other issues though. If the fitting in the side of the caravan is damaged, you would need to consider replacing the entire water pump. hose connector and the wall fitting. If that is the case I would suggest looking at Whale products as well as the Ultraflow models.