Quick Clear button sticking

[TechUser]

Just noticed the other day that when I pressed the front windscreen quick clear button that it stuck. No matter how many times I pressed it the heater remained on. I eventually was able to turn it off by pressing and holding in the button below and 'picking' the stuck button out.

Does anyone know how to take the button out and replace it or indeed any ways that I could fix it?

Any pointers would be appreciated.