I am just investigating the same problem on my machine. I found it to be the water inlet valve which is connected to the water inlet hose. looks like you can get this for around £21 + PP. Turn machine off at mains. Disconnect inlet pipe (after switching off water). Undo the 4 or five screws around inlet. pull off the white plastic cover and now you have access.
pull off suction tube, two electrical connections and disconnect water pipe. Replace part & reconnect. Merry Xmas.
Eddy the bluenose reindeer, November 2007