@Duvel It is the medium size (you can put inside 8 skewers) but it probably looks bigger in the photograph. In the manual they recommend using 1.5-2 kg so I think that the Weber chimney will be sufficient.
@rotuts, I don't have the charcoal chimney yet (that is why I was wondering if I could use it before I bought it). They do have instructions and a video on how to fire it up (and I have done it with mixed results ;-) but I love how easy it could be to do it using the chimney. I am not in the UK but I can send them an email with the question (never thought of that :-P)