Have you checked the filter on the inlet pipes where they connect to the machine? The gauze inside the fittings gets clogged up. It might look like it's filling faster for the wash if the machine draws hot and cold, but then will appear slower when it only draws cold for the rinse.
I have one of these out on loan, so when I get a chance I will look and see if there might be anything else.
sparkyfixit@westways-multiskill.co.uk, January 2007