Hi Andrew, i know the reset process for my model wm 5121 s and i do think this goes for most models...youtube do a short video to show you the process. This worked for mine first time. Its a diagnosis test.
Turn machine off at the mains.
Open the door.
Turn mains back on.
Set at 90 degrees or highest cotton wash.
Close the door.
Whilst holding start/pause button in press the on off button on, still holding the start/pause button and continuing for about 3 seconds, turn the dial to the spin/end . Then you should see all lights flash. Go through the 10_11 stage process . This should then reboot washer. When you have reached the end, turn machine off, then turn it back on and this should let you do a normal cycle. Unsure if your model is digital, but do try youtube for a step by step guide too.
Hope this helps.
Heidi, October 2015