I think I have it licked now - urgh.
I fitted spare master socket at the remote end, and cheated.. I took the "home" master out of the equation and have a single pair pair to the cabin.. Now all is well.
Eventually, I think I'll devise a switching system so that the broadband can be used at either end.
My main reason for wanting to get broadband into the cabin is because of the interference and signal dropouts that get worse as the night draws on.. I have been using a high power (1 Watt) mast mounted wireless 'card' which is reputed to be good for a couple of miles.. It's an Egasky MARS jobbie (can't recall model number) available via the bay.
Of late, there has been a lot more internet traffic in my location, and it seems to knock out, if that's the term for it, my wireless signal.. The problem being that the PC would then throw a hissy fit and refuse to reconnect to the hub unless I rebooted it first.. It got to the point where I was rebooting five or six times in an evening.. The worst was eight reboots, and that's a lot of wasted time!
I might just try Terry's idea of adding a bell capacitor at the remote end and see what happens with the master reinstated at the 'home' end of the line.
I reasoned it out that it had something to do with the three wire setup, and then remembered that the broaband will only work if it is taken off at the master socket.. I have to admit, I couldn't remember why it needed such a long DSL lead for the hub, until it dawned on me.. I've been here before, and the hub won't work on any extension socket.. All it will do, is to search for the broaband signal, but never detect it.
At the moment, I can have the broadband, either at the home end, or at the remote end, but not both.. Since I spend all of my internet time on the PC in the cabin, for now, that's where the broadband is routed to, until I try a bit of jiggery=pokery to see if it can be made to work at both ends, ergo, Terry's bell cap idea.
Of course, if I was adventurous enough, had the time and patience, and enough know-how.. I could set up one of my InDeX PABXs with ADSL extensions... But, not tonight, Josephine.