Lose channel4 & discovery
 

I am based in Dublin, Ireland and receive an NTL signal. I have the signal split. Signal A goes to NTL digital box and all channels are received okay. Signal B goes to a 4 way booster/splitter to 4 different tvs around the house (on coax cable). I receive all channels on signal B except Channel4 and Discovery - any idea of the cause? If I use a splitter (no booster) for signal B then those channels appear fine!