I know this is years out of date but in case someone else ever finds this, there are two little yellow 'cage' filters inside the water inlets on the back of the machine. Turn off the taps and unscrew the hoses from the machine - then use a small pair of pliers to very-carefully twist and pull the 'tab' of the yellow filter. You should be able to remove it and clean it - hopefully this will solve the slow-fill problem.
Alex Shepherd, January 2008