Thanks very much for all that! Much appreciated!
Right. I've been up there and had a look. The coloured part on the tip is brown. ..so that means its a group E aerial, and you say that dover siteB doesn't carry all the mux's. So, if i've understood all this correctly, that explains why i have never been able to view certain channels, and the weakness of my cheap aerial explains the unreliability of the others. ....so, as dover siteB doesn't carry all the mux things, I should be looking to get the biggest, baddest, high-gain group C/D aerial I can find, with a mast head amplifier. Is that my mission as it stands?