Twin Feed LNB for Humax Freesat Problem

[minx]

Hi

I have a Humax Freesat twin tuner HD receiver for use in France. I have a fixed dish set on 28 east. I can get all the Freesat channels available in the U.K.

I wanted to use the full twin tuner functionality of the Humax to watch one channel and record another. So, I bought a Technomate twin feed LNB, a second length of coaxial cable. I now have two coax feeds from the LNB each lead pluggged into the separate tuners of the Humax.

However I'm disappointed to find that, whilst I can record two channels at the same time or watch one and record another (or indeed record two channels and view a previously recorded channel), there are only a limited number of channels available. Some of the channels appear greyed out on the channel list, when recording another channel. I'm not looking at viewing another satellite, just want to have the option of all channels pulled in on 28 east, using my twin feed LNB and to be able to record two or watch one and record the other.
When I only had one feed, I could record one channel and watch another so long as they were both on the same transducer. I did think that the twin feed LNB and second coax cable would give me what I wanted. What have I misunderstood? Right p***ed off as I was all set to watch The Golden Lady on BBC2 tonight and to record Hinterland on BBC4. At 9pm when Hinterland should have started recording, I got a conflict message and had to cancel the recording so as to continue watching The Golden Lady.

Thanks