That is indeed different, and doesn't solve OP's problem.
Situation is as follows:
1- no recordings going on, the box will use the fixed disk for tuning (live-TV);
2- during this TV-watching a recording starts; as the fixed dish-tuner is now not available, the motor will be used instead.
Result: although only one recording is going on, live-TV watching is limited to the use of the fixed dish.
If one would have the choice to choose a tuner for zapping, the motor-tuner would have been chosen for live-TV. So whatever which recording is being started, the motor is still available for live-TV.
So a perfect solution seems to be an option in settings for preferred tuner for recordings (in this case would be set to the fixed dish tuner) and a setting for preferred tuner for live-TV (would be set to motor-tuner in this case)
Just to add to this:
It is only a problem with timer recordings, if you do an instant record it will use the whichever tuner is being used for the current channel (live tv) and leave the other one free.
For example last night there was something on Tuner A (my fixed dish) which my wife said she wanted recording just as it started so I did an instant record which then left Tuner B (motorised) free, with a timer it would have used Tuner B if I had been on another channel with Tuner A and tied up the motorised dish