I have the YouView G4 box and you'll be pleased to know that I have the same setup that you are talking about. The box is permanently connected to my main TV with an HDMI cable and to my TV in the bedroom via scart connected to a RF Modulator. I get all the menus in the bedroom. An extra remote for the YouView box (BT charged me £10) is handy, then you don't have to remember to take it to the other room.
Hope this has helped.
I got a Mercury 350.111 12V 250Ma RF Modulator from Amazon. It works just fine. No problems in 3 years. I originally bought it for my BT Vision box.
Does this RF Modulator arrangement also work with the original BT Youview box [Humax DTRT 1000 model]?
Yes, it does. I'm also using the Mercury RF modulator from the SCART output of my DTRT-1000 to feed a TV upstairs, everything works fine.
I have the same setup using the same modulator and works fine. if you dont mind me asking what do you use to control the box as i have had mixed results with IR senders of various types.
I'm using Philex remote extenders. I've had them since my original silver BT Vision box, and they still work perfectly with the YouView box. Never had any trouble at all with them on either box. They work just fine from opposite corners of the house, between floors. Not sure if you can still get them, but here they are. Other makes may work just as well - these are the only ones I've ever used.
I currently feed a bedroom from TV from the back of my youview+ box, I have a scart lead connected to a RF modulator then a co-ax cable up the wall to the Tv. I also have our main TV fed from a HDMI cable off the back of the Youvew box. The problem I have is that when the Main TV is off, then I am unable to view any HD channels, or any of the extra channels over the internet, on the bedroom TV. its as if the youview box needs to know its connected via HDMI to something. When I turn the main TV on, i can access all channels no problem on the second TV. Any help woul dbe greatly appreciated. Thanks.