An update if anyone is looking. I have taken the dishwasher apart and checked the pump, when the pump was connected outside the dishwasher it worked fine. However the sump below the column gasket was full of debris, which I cleared to the best of my ability. The main problem being, is that the sump is a moulded part and as far as I can tell can not be removed, so that it can be cleaned properly.
Having cleaned the sump the dishwasher does drain but still not effectively.
Any advice, please
Baffled, July 2007