The Clash Singles box set (minutiae)

[TVC]

I have the 2006 UK release of The Singles box set which has a number on the bottom of the outer case. I assume it was a limited/numbered release but there seem to be plenty of new copies still on sale so I'm now wondering if it really was.

Does anyone know for sure? (I've failed dismally in my attempts to Google the answer although I do now know that there were US/Japanese numbered releases!)