use an old video recorder
scart from sky to the video recorder the RF out to the TV / TVs
you can then have an extra channel (6) to either play video / dvd / sky / security cam on all the tv's at the same time or individually choose from the 6 channels on each
i have 5 tvs setup running from the RF out of the Video Recorder with one booster and this is a perfect picture
i use for playing MTV for parties, Security cam or whatever
if you need to change the sky channel from the tv upstairs or conservatory etc you will need a remote remote (infrared eye thing) or get up and change the channel
or preselect your veiwing selection and it changes channel itself.
cheers