I think most of them exist, even if a few are still waiting for restoration (a costly affair), or have not been seen for years. Most people don't realise the sheer size of these cars. They are much wider inside than a regular Mark VI, and the driving position is rather odd, because the steering wheel is nearer to the centre of the car than usual. I have only driven one (a ten recently restored example, RHD, with the upright nose) once, and not at a great distance, but this is a fairly heavy body and the performance is not fantastic. It paved the way for the mindset of Bentley Motors to allow the R-type Continental to go ahead though..