The screenshot of your hub stats shows that DLM has reduced your speed in an attempt to stabilise your connection.
Is there any noise if you carry out a quiet line test by dialling 17070 ?
I have done the quite line test and there is no noise
Have you been restarting the hub in an attempt to improve your speed? DLM considers your line to be faulty and has taken action
I haven't restarted the Hub in months, what is the DLM ?
your connection time is only 2 days so hub appears to be dropping connection
your attainable speed is low compared your dslchecker estimated range are you able to connect to test socket with filter and see if that makes any improvement?
https://community.plus.net/t5/Library/FTTC-DLM-What-it-is-How-it-works/ba-p/1322799
Dynamic Line Management is an automatic system that monitors every line and takes action to achieve the best speed possible commensurate with the line characteristics. If it detects instability or impairment, it reduces the speed to stabilise connection.
Your line would appear to be faulty, hence the reduced speed.
I know where the main socket is but not sure about the test socket ?
which master do you have and are you using master socket
I had a problem at the end of last year where I was constantly loosing connection which was resolved by an engineer visit.
Master socket 7