I worked in education for many years where Boxford 160TCL / 240TCL / 260VMC machines were used. Having retired I managed to purchase a 160TCL and a 260VMC that I'm in the process of restoring. They are both from the BBC B era but have had serial interfaces fitted and the 260VMC has also been additionally modified with the self-homing switches. Both are working despite some neglect over the years and are being repainting prior to a good overhaul. Unfortunately I don't have a manual for the 260 as I would really like a wiring diagram for it.
Hi Stuart, welcome to the forum.
I also have a 260VMC at my local hackspace (http://rlab.org.uk/wiki/Boxford_260_VMC). Its in pretty good condition and runs with the full Boxford PC software. We haven't been able to find any decent documentation either though I'm afraid.
We are still deciding if its worth converting to Mach3 (if it wasn't working it would be an easy decision!).