I don't know about the question mark but I do know that �McDonald�s. But not as you know it.� is set in my font Houschka (Light, I think, but couldn't tell as I was driving past the poster at the time).
G-Type through Veer.

Does anyone have an image of that ad/billboard? I'd like to see how they handled it.

There's a small image here. The story has been extensively covered in the UK press, so I'm sure you'll be able to find more.

the link requires a sign up to the guardian members area ...

What a pain, sorry! (I'm already signed up, so I didn't notice.) I bet you don't have to sign up to view the image though: try here.

Thanks Robin, do they only have a salad shot or is it a campaign

I believe it's a campaign. (Haven't actually seen any of the ads - only read about them!) Obviously there won't be any shots of burgers and fries. According to the Mirror, the posters feature "wholesome images of lettuce leaves, frothy coffee and free range eggs". Don't think it'll convince me to go there!

It is a billboard campaign featuring a large image on a white background, with black type and a hand drawn question mark - (not part of a typeface) in the same colour as the golden arches, all quite understated. Typography by Mark Cakebread, Leo Burnett, London.
What is all this about a closely guarded McFont? - it doesn't exist. Anyone can buy Houschka.
I may have a pdf soon...

Uh oh -- don't go there: http://typographi.com/000537.php