Nick, thanks - I'm looking forward to many fun projects with this; and part of the reason I built it is to be able to get in close with the cutting bits

Bogs, thank you. You do have a lot more experience though, so there is always something interesting to learn from you. I'd like to think that I'm now learning things that I can also pass on to young novices 30 years from now.
I didn't do much in the shop today, but managed to squeeze in time to drill the chuck for the tommy bar, and also made up a matching tommy bar and c-spanner from some 6mm silver steel. For the c-spanner, I turned the tip of the length of silver steel down to 4mm. After this, I bent the curve in around a piece of 30mm rod - when I released the tension after bending, it sprung back to a nice fitting curve for the collet nose. Bending the silver steel was pretty tough going, and it got pretty warm from internal friction!
Then I picked up a scrap piece of flat iron under the bandsaw and drilled a 4mm hole in it at a slight angle, and silver soldered it to the bent drill-rod to make a nice hook. Used the bench grinder to grind the lot to a reasonable shape, and finished off with a file and then sandpaper.
I also turned 2 pieces of 10mm aluminium rod into a matching pair of handles, and loctited those to the c-spanner and tommy bar:

Now all that is left, is to make a nice wooden storage case for the chuck, accessories and collets - this I'll do in the next week or two when I plan to do some work on my kitchen cabinets - I can do OK woodwork, but don't like the mess, so I'll lump all the woodwork together in a single go.
Regards, Arnold