Thanks for the comments Pete & Tim.
I decided that I have to get to grips with the wire threading issue. It breaks down into two areas:
a/ The lower guide is in a confoundedly hard place to look at
b/ I'm trying to thread a 0.25 (and possibly burred in cutting) wire through a hole that is allegedly 0.255 mm diameter
Now there's not much that I can do about a/ (I think most modern machines run their wire downwards which would help) but I did a bit of research and asked a few questions on a professional forum about the actual wire and it's cutting. Apparently in early Elox machine manuals they advocated heating the wire with a cigarette lighter, and stretching it to break. Another manufacturer embodied a pair of pillars with a voltage between them - stretch the wire across, anneal it and stretch to breaking point.
I tried the cigarette lighter method - it works and produces a thinned wire, but I'm not a smoker and the lighter is hard to manipulate as the wire is held taut enough to break. Strangely I'd thought of the electrical method independently so I thought that I'd do an experiment.
Digging out a 12v transformer, I rigged a pair of screwdrivers in my vice, holding them with non conducting soft jaws. Drivers about 3 1/2" apart, 12v on the wire - touch it on and POP

instantly the wire melts - volts too high.
So out came the ancient variac that I keep for scaring Health and Safety people

A bit of experimenting came up with 3 volts being enough to anneal the wire. Takes a certain technique to take it off before it breaks, as if it fuses rather than breaks it forms a ball on the end.
Anyway from this crude test I've shown that I can taper the wire from it's original 0.25 mm to 0.13 mm - half it's thickness. It is possibly worth making up a little fully insulated box with a couple of pillars poking out, that I can use to stretch wire ends. (or I could stick with a lighter!)