In Clacton, you will need to re-tune the TVs to connect to a different transmitter (Dover)
In London, you were probably tuned in to the Crystal Palace transmitter.
Let me know if re-tuning the TV sets works for you :)
(the few channels that are still working may be picking up a weak signal from Crystal Palace, but re-tuning should get you a much stronger signal on all channels)
We have tried retuning all the tvs again but still nothing so I have called in a tv man who has fitted a booster box to get it working
Ok, if you are in an area where the signal is weak or the aerial is not very strong, you will need to use a booster.