Just a quick update. Engineer has been and gone. He said my line signal was a bit weak. He couldn't boost it from the street box, so he has fitted a signal booster in place of the old splitter.
He's also passing the street box on to the Network guys, as he said the figures he seen for all the "switches" were unusual and all too similar to one another and something he's not seen for a long time.
Not much i could say to that as i have no idea what he meant
Cheers for the replies