Window button sticking

[Zippee]

I have a problem with my passenger side window that started on Saturday. I first noticed the window didn’t drop when pressing the door opening button. A press and hold of the down window button would lower it but let go and the window automatically closed. A little more investigation and the bottom button has a nice click to it, the top button appears stuck, just a squidgy press if that makes sense rather than an on/off click.
First question is has anyone had this happen before and if so how did you sort it? Is it just a case of cleaning the existing switch or did it require a new one?
If the former then how do you access the switch itself?
If the latter where can I get the part? I’m assuming I don’t have to buy the whole metal piece and can get just the switch behind?

[Zippee]

Thanks. I'll have a look later this week.