Ever since we bought a new LG digital television,reception is pathetic on Channel 4 particularly,and ITV 1 and channel 5.Is this the set,the aerial or the area (near Sudbury,Suffolk)?

One problem with digital television is that the carrier frequency of the channels was shifted to a higher frequency vs the old standard . These allotted frequencies require a whole lot more output power at the stations as well as they follow a straight line and the bounce (reflect) off of natural objects such as tree leaves, rain drops moisture, power towers etc. In other words unless you live right next to the transmission tower, you get a lousy picture. Since it is a digital signal, and your receiver does not collect more than a significant portion of the transmission signal, it cannot render the picture so, drop outs causes loss of signal and no picture at times.

That is why most people go to cable or satellite to get a continuous signal.

I would say that unless you put up a good active antennae, you will not get a decent picture. Even then you will not be satisfied. The stations will have to do a lot more work on their signals and up there power levels to compete with cable, but hey, they don't care about their over the air signal since they can sell their signal to the cable operators for lots of bucks and reach more eyes for their advertisers.