Thanks Dave,
I did find that part number as you suggest by searching my dishwasher model but trying to cross reference the code on the grey part ( eg my part has 5600044792 on it) with the Bosch part number then check if that will fit my model is a bit tricky. Other than I what think is a turbidity sensor in what is a blanked off port on my heater, its difficult to see what other difference there is.
Thanks for the advice about the diverter, I will have a good look.
Rob