At present I still have not managed to overcome the hot end problem, but once the temp is reached the warning siren sounds, and I switch the hot end to off, and repetier makes no further call to the hot end.
The machine is performing well with a pen as a plotter, although I did have trouble with Z axis creep, cured by adjusting G2 and G3 settings in EstlCam. Seems like the Melzi just can’t handle them. Curves are generated as a multitude of tiny lines, which slows the progress down somewhat, and sets up a bit of vibration.
Now for a spindle!