The A1200 is a Low Density drive, like that of the A500. It is slightly different shaped, and I didn't have a ton of luck transplanting a floppy drive out of a dead 500 into a 1200, but I think that drive may have been damaged. It SHOULD work. I have not, personally verified that it WILL work, though.
Does anyone have a spare Amiga [HD] cable with a diagram for installation??
This is just a straight-through cable. Attach from pin 1 on Amiga to pin 1 on the HD.... done.
Wouldnt a PC Floppy drive cable out of interest? If so I am sure you should be able to find plenty at a local PC hardware shop
Yep... The ends are the same... just make sure you have the proper Amiga twists for whatever model you're hooking it up on. Also, make sure you set up pin 1 to pin 1, and you're set.