Found a few of these yesterday mixed in with hundreds of rusty Antique safe blanks. They are unusual in that they have tapered bits, a strange collar two thirds up the shaft, and round bows instead of more usual oval. They seem to shout Chatwood to me, and the bit matches the Chatwood in photo 2, I wonder if there were early single bit versions that had tapered bits? The Chatwood similarities could of course just be coincidental and that they are just boring old night latch blanks, but can't help thinking they might be a bit more special than that.
Click image for larger version.  Name: image.jpeg  Views: 30  Size: 414.5 KB  ID: 20573 Click image for larger version.  Name: image.jpeg  Views: 23  Size: 119.0 KB  ID: 20574