If BT extended the master socket then everything before it is their problem.
The only thing usually to look out for is if you have any phone extensions from the master socket, make sure the bell wire is disconnected. (I forget which one it is, I'm sure its mentioned somewhere on this site)
If you have a filtered master socket then Its easier to test if you have a plug-in microfilter and so can remove the screws and the filter off the master socket and use that plug-in one instead. I had to do that recently as my master socket filter stopped working.
You certainly are connecting well below what you should be, though I can't see any obvious reason why from those stats.
