All you guys with your posh 80s. The slider cable on my HZ goes directly to a manual tap/valve on the bulkhead, open is open, closed is closed, job done.
That's exactly what I thought on mine Clive, it was only when I pulled the dashboard out along with the heater controls I found there was no cable in sight that I investigated further.
Anyway, you know 'less is more' right?

Regards
Dave