Confused. It's a 1000S and only showed a signal at Tuner 1. When I connected the 'good' lead to Tuner 2, Tuner 1 showed 'No Signal' and Tuner 2 (which I would have thought would now be working) showed no message at all. The Humax still stated that 'The box is connected with one tuner only' even although no signal was being detected at either tuner.
This got me thinking that the box was 'stuck' in single tuner mode so reconnected both leads and did a factory reset and now have 100% Quality on both tuners!
Dish man has been cancelled for the time being.
Thanks for your help guys.