Hello Peter,
This is the dial fitted to mine:

I don't think it's an original part though as it looks homemade. I've had a look at the manual and there is no mention of a screw cutting dial so possibly the lathes didn't have one when originally built. I would expect one fitted at the factory would have had a cast body.
It looks pretty easy to make one. Couple of bits of bar soldered or welded together, with a spindle, dial, and gear wheel.
John
Just had another look at the manual and there should be a leadscrew guard that bolts onto the end of the apron where mine has the dial. That was obviously taken off and lost when the dial was fitted.
Edited By John Baguley on 25/02/2016 12:14:42
Edited By John Baguley on 25/02/2016 12:23:41