[multiskilled]

You will have to retune your second tv or change the rf output of the sky box usualy the default setting on the sky box is ch69.

It is better to change the setting on the on the box as you know there is no interference on the the channel the tv is tuned into.
press services 401 select on sky to access hidden menu then choose rf outputs change channel no, it goes from 21 to 69 try each one until you get a the menu on 2nd tv then store the setting.