I used a 760mm long 25mm black starter cable, with a 6mm lug on one end (for the battery end) and a 10mm lug on the other (starter end).
I drilled a suitable hole in the bottom of the battery tray, then ran the wire between the spare 6mm thread on the neg clamp and the top starter securing bolt. I then cable tied the cable along the original harness for neatness.