Thanks everyone, sounds like I was on the right tracks. I did build a D10 as a kit of machined castings years ago, was fun but I can imagine the tolerance on something so small would be less forgiving. Machine wise, I'm looking at several mills, I had thought about the Warco WM18. I'm thinking a lot of work would be easier in a good Mill rather than trying to Mill in the lathe.
One stumbling block, I'd been looking on line about crankshafts as there is no cast shaft. People are talking about machining from sold, is this the way to go or individual parts pressed together ? I haven't got the drawings as yet so am just thinking aloud.