Max-Arc, made in Walton on Thames, Probably not as good as a modern inverter, but they are both decent quality welders that can happily run all day:
I've actually got two of these, the one shown is a 200A model, and the other is smaller, maybe a 140A (buried under a bench at the moment). Both are the same layout, with the crank handle and the sight glass with the two scales. I was slightly wrong with the voltage terminals though, they're actually 55 and 80.
I would guess that I could use the scale shown by Gaz above as a rough guide for mine, ie the 80v setting for thin sheet and special rods, and the 55v setting for thicker stuff needing more amps??