What did I say try 'Parts for Mercedes-Benz' website. You did and you had a result.
Pays to listen to an Old Man sometimes.
You just need to know what the part is to start with.
On that subject got a switch in my interior light god knows what it is gonna have a post a pic and ask methinks.
Glad the part was so cheap let us know how you get on.
Merc dealers/specialists are probably the way forward in this country as so few XF's sold here