some good suggestions on here.
I have similar quandary – our house setup was put in by a cowboy pre-loft conversion and worked fine till the other day when we upgraded 8 yr old Sky box to HD. The digital aerial lead used to go direct to the Sky box, and an RF out then went from box to a powered splitter in the loft area, with aerial outputs to all the other TV’s. This gave us Sky in all the rooms, plus digital TV in all the rooms also. Because with HD Sky box the aerial wire now goes to the TV, the IO RF output from the box only transmits Sky round the house, not Sky plus digital TV. We now have no digital signal anywhere except main tv. The aerial sockets on all the other TV’s are connected via the loft box to receive Sky, which is good, but I can’t see any way of getting a digital signal in there too, without lots of holes in walls, new cabling etc …