While stripping down my own RB, I found this cast tag on one side.
Attachment 417049
"WR 6064" - I've been trying to figure out what it means/meant?
In doing this research, conclusions are all very well, but I prefer actual evidence. I think I've finally found proof that these RBs, and the twelve machines supplied in the 1926-30 period, really are the same machines (i.e. that it's not just a coincidence).
The penny finally dropped: taking a closer look at this document of 17th September, 1930, you can see that the Order No. for the 12 "Bench Planers H.S." was "W.R. 6064"
Attachment 417050
I think that pretty much confirms that my Wadkin RB 116, along with RB 109 and RB 113, are from the batch of 12 - and therefore confirms that these (and by association RB 117) date back to 1926-30.
Footnote:
I neglected to mention that these files are held at Archives NZ in Mulgrave St, Wellington.
Cheers, Vann.