P - N it was after my time, but one seat was removed and the remaining nav seat had a rail which allowed it to slide across between the radar/plotter positions. I have to confess that the tanker nav radar's job was not the most demanding in the RAF, but in our defence we did a reasonable number of single nav trips when tanking was not going to be involved, such as air tests, pilots' instrument rating flights etc. I'm guessing that single nav in the final years of the K2 must have been quite busy at times.