Ok, the real reason for the rotary control being on the right:

The plastics for the Mk2 were done very late - and we couldn't afford not to ship the mk2, as rather a lot of money had gone into the production (Steve was looking particularly white for those few months, but managed to hold it all together :) ). So, as a last-ditch backup plan, we planned to be able to switch to a slightly modified mk1 panel if required. The only spare space on the mk1 was to the right of the display.

You'll notice that the hex standoffs and the buttons are in *exactly* the same place as they are on the mk1, which is why some people have managed to pretty successfully fit mk2 panels onto mk1 players :)

Hugo