The drawings are also available - see the link in the above YouTube video.
Turns out it took me three attempts to finish this properly. A variety of reasons: not measuring carefully enough, not thinking through the work holding, practice runs at threading and knurling, and generally cocking it up!
Very pleased with the results and learnt a lot along the way. Finished it off with Caswell's Black-Ox kit and that has worked perfectly! More info about this process can be found here.