Whirpool WWDC7440 on/off switch issue

Hello. We have a Whirlpool 6th Sense WWDC7440 washer, about 2 years old if that. The on/off button has always seemed a bit flimsy. So a few days ago the button just pushed in without the usual click. I've removed the front control panel and discovered that rather than a solid on/off switch there is essentially a flimsy piece of plastic with a point on it which is supposed push a microswitch on a pcb. But it has snapped. I've ordered the £5 plastic part. The question is how to fit it. The most obvious barrier is that you need to get the selector knob off to move the controller box away from the front...but how? Ive tried to remove the selector knob from the front side but it wont shift. You tube videos show american washers have a button behind the knob which you press to release. But the back of this knob is covered by a red plastic block which also has a wire attached. The wire just clips out, but I'm not sure if the red block is removable. Any ideas how I can remove the selector knob or indeed any advice as to fit this piece of on/off switch plastic. Thanks.