If you're after new battery cables, go to your friendly neighbourhood auto electrician. We recently had new cables made up for our S1 and S11 and they cost no more than generic stuff from Supercheap etc. The new ones are also the length I wanted and with correct size lugs on each end. Saves trying to tighten a cable with a 10mm lug onto a 1/4" bolt etc.

Sounds like you need new spark plug leads as well.