Which diagnostic tool for R56 cooper?

Hi, I've got an R56 cooper 2006, had since (almost) new. It was one of the original demonstrator cars for the R56.

I want to buy a diagnostic thing to plug into the ECU and I was wondering if anyone knew which ones work on the R56?

I've been looking at eBay and most say they work on the R50/53 but don't specify the R56.

Can anyone help?

Thanks :)