Whale pump outlet hole not in line with truma ultr

I am having problems with my water flow into the caravan. I had to fit a new truma ultraflow compact housing earlier this year. I already have a Whale EP1642 pump. Used the two together for the first time this weekend and although it all seemed fine initially the water pressure was not great and the flow has now stopped. It seems like the whale pump isn't working correctly but before I try another I noticed that the truma housing inlet has the hole central but the whale pump outlet has the hole to one side. Won't that affect the flow into the caravan? The outlet hole must be virtually blocked by the wall of the inlet housing as the holes do not align. Before i buy another pump does anyone know if the housing i have fitted does not work with the Whale EP1642? Tried searching the internet but nothing seems to mention the actual outlet and inlet holes. Thanks.