I have noticed that many people asking for help with tuning Freeview don't specify a lot of information (some give none). If people have old VCRs, DVD Recorders and/or old Sky boxes should power them down completely, even unplug from the wall, then run their antenna cable directly to the TV before seeking help. This would at least remove the possibilty that they are getting interference from a UHF modulator incorporated in old analogue appliances. If their picture is OK when they do this then they obviously have a connectiom problem or some sort of interference with/from their other equipment. Since the digital switch over there is now no need whatsoever to have an antenna connected to a VCR or old DVD recorder. The only use for connecting the rf out from such a device to TVs is to allow old TVs (without composite A/V) or TVs in other rooms to receive signals from the VCR, DVD or Sky via a modulator either inbuilt or external. Any modulator any where in the setup has a high likelyhood of causing digital reception problems.
Basic rule of thumb.
Start with single TV connected directly to good UHF antenna with high quality co-ax. If that works OK then start adding extra equipment and connections til faults are found.