Not sure how it works in the UK but over here some colours are not available on the R-Line for example Ruby Red which is strange as the picture you posted is an R-Line in Ruby Red. Habanero Orange, Caribbean Blue, Moss Green being other examples not available on the R-Line.
Probably worth a visit it to a dealer and clarify the colour options available.
In South Africa we can spec Ruby Red with the R-Line but not Caribean Blue. Seems very strange that certain paint colours can't be chosen with the R-Line and that this also seems to vary from country to country. You would think that if a particular colour is available that the customer should be able to choose it.