Thanks for all the input guys - as a newb to messing with steppers (aside from the experience with the 3D printer I've built recently) it's all informative, interesting, and useful. Please don't snipe at each other though - I appreciate all the different arguments and perspectives.

I will indeed meddle with it all but it'll likely be quite some time before I can assemble something anyway in all honesty due to the need to come up with hardware. If I fry these steppers in the process it'll be a shame but I won't be upset, as long as I don't take out any drivers in the process of course!

I think I have one or possibly two more of these steppers spare as well but I'd have to check.

I need to figure out I'd be better looking at those X3 bits on offer over the stuff on ebay but I'm not yet sure entirely about the pros & cons of both, relatively speaking.

And after that I need to figure out mounting hardware etc. I did have an idea that potentially I could fabricate temporary mounting hardware for the steppers using my 3D printer, just until the mill can machine its own ally stuff.
People probably scoff at the thought, but the printed plastic has an awful lot of strength and I'm sure would be capable of doing the job just fine. Nothing really to lose by trying anyway.

I'm not learned in making 3D designs though and have limited free time, so if I can find .stl files for the hardware it's a huge headstart.