Thanks Mike for all the info and the kind words :-)
I don't know, I think Jaitea's picture is a bit over the top. But yes, what you'd need to do is to increase saturation. Unfortunately whenever I increase saturation over the original value in Premiere, it creates these weird colour artefacts as seen very clearly in this picture (though it affects all the shots to a certain degree):
I'm gonna try and pull the scene into AE and correct it there. Would you guys agree with me that it looks good in the WP until the point where the sand people attack Luke and that it need saturation boost until the wipe top Ben's hut?