to reach the bottom of the machine, there is a plastic cover on the rear of the machine where the pump's grey hose is comeing out. locate and unscrew 2 or 3 crosshead screw's round the edge of this plastic cover. now just slide it to the left (i think) and lift off. there is quite easy access at the bottom.
oh yeah, don't forget to swich off the machine!!!
mr i have a wt960, February 2008