I just saw Farncombe Pop's post on NSRA site, looking for a cable for Jag IRS, I think you're sorted now?

Anyway, I found that a Morris 1000 cable was perfect for the job, (on my Pop). it even has a built in bolt, so you can fix it to the chassis.

My handbrake was still 'kin useless, but the cable worked a treat!!

There maybe other cables suitable now, but back then, that was the best fitting one, correct length too!!