Connecting to test socket may improve your connection as it eliminates all your internal wiring from causing a problem. You need to check when conencted to test socket that your phone extension sockets do not have a dial tone
I have tried this with no great change to test results. I have been told by on of the several engineers that have pretenteded they where trying to fix my issue that 22 mbs was the optimal speed for my line as the cabling is not really fit for broadband guven its age. He also told me that he had been instructed to say that about my optimal speed not the state of the cables regardless of whatever tests he had done said.