NT,
The old lens is a Zeiss Ikon NOVAR ANASTIGMAT 6.3 (or at least that what is written on the front), I actually kept the lens which is now mounted on a Linhof Board, I would have kept the lens on the camera but I need to use filters and a few more speeds that the original gave me.
If you look at the picture of the back of the camera, the holder actually has a piece of ground glass, that is how I focus the camera, dark cloth and magnifier, the whole works, and yes the film plane has shifted with the new new back.
I will either take some pics of the back or ask John "my crafty friend" to see if he has any detailed pictures of the process.
Will be back
Hugh