@adamwalker this is where I'm dubious. The bridge tap had been removed from the picture for quite some time ( literally the cable was disconnected) by engineer number 2 and the drops still occurred. The high resistance problem never showed up until much later after this disconnection. All four engineers agreed that a data extension would not cause a drop out problem, and its removal for testing proved them correct. All four also stated it could be reconnected after the problem was found and that it was in fact the way they would instal it themselves.
The high resistance problem turned up somewhere between visits three and four, so wasn't present when engineers 1 and 2 visited ( 2 physically removing the bridge tap) so by the process of elimination both of those cannot be the cause. I can only conclude that either I have been visited by four very poorly trained engineers ( doubtful) of the fault was found somewhere else. I cannot see the replacing of 2 Master sockets as being the bully moment.
It's very odd.
