I've got the 8.25.
I think I see where you're going wrong: the Cherokee drum brake shoes will not fit inside the new disc brake setup, so you will have to get GC handbrake shoes, springs (top & bottom), adjusters, the little pin things and retainer clips that hold everything together (this is all for inside the drum/ disc assembly), then use the GC handbrake cables instead of XJ ones. You can reuse the XJ ones and use a cable clamp, but I couldn't go with that becasue of the UK roadworthiness test. Search on here - there's lots of info.