I looked around
www.RealOEM.com again. Maybe I am missing something but I don't understand why BMW's Performance SSK would not work on a RHD car. The shift pattern is the same as are all the OE parts. Here is a quick comparison of 135i (N54)euro LHD vs RHD models...
LHD stock shifter parts
25117524720 carrier
25117581806 shift lever
RHD stock shifter parts
25117524720 carrier
25117581806 shift lever
As you can see the shifting parts are the same for RHD and LHD models. Maybe the shift bag is different? I really don't know why the Performance SSK would not work. ?
LHD Performance SSK parts
25110434218 carrier
25110434217 shift lever
You will also need a new plastic bearing for the shift lever and some extra c-clips incase any of them break or go missing during the R&R.
25111220600 bearing
25117571899 c-clip