I have bought a replacement pump for a Bosch WFO2265GB/01 (PMP230). The previous pump that failed was itself a replacement about two years ago. The problem that I have is that the pump housings are different sizes so the new one does not fit. Could it be that when the previous pump (labelled B20-6) was changed the engineer changed the housing too? Is it possible to buy a new plastic pump housing? I have seen them attached to a pump but as I already have a pump I just want the housing. Any advice welcome. Thanks