Should I check to see if Bell Wire etc are connected from the junction box (see below) to the master socket and if so cut them?
Wont harm - it looks like there may be some room for improvement and its much cheaper than an i-plate.
I have not manually re-sync'd at all during the 10 day period although I have a number of LOS's (not sure if they cause a resync) -
LoS means loss of signal - its actually an alarm state which doesnt necessarily mean a loss of sync with the exchange - it depends how long the LoS was for.. but it is one of the most serious alarm states and indicates some sort of noise burst.
Checking your internal wiring would be a good move.
I notice your router seems to indicate uptime of 1 day 22 hours so it perhaps did an auto resync.. but Im not sure since your sync speed is around the max for an interleaved line.
If I disconnect router to check Bell Wire or just do a resync am I likely to lose speed/profile? Would it be best to do this in the morning when my SNR margin is at it's highest?
As long as you dont mess too much and keep rebooting the router it should be fine.
Morning is best to give you the most speed, but doing so can sometimes cause the SNRM to get too low in the evenings, which may cause an auto-resync in the evenings. Evenings is the worst time if youre looking for speed, but best for stability. Its hard to say without 'knowing' how your line performs and how much the SNRM dips.
. Interleave - Should I ask to have this switched off? Will it really improve my latency by 20ms or more? Potentially how much speed could I lose?
Yes it will.. You wont loose speed as such from your current profile. You will hopefully sync at the full 8128 which should increase your ip profile to 7150.
What effect it will have on your stability and error rate though is hard to say - check your wiring first.
Based on your attenuation only you should be fine.
However noise margin drops significantly in the evening down to the 7-8 range which has an effect on throughput.
That I am concerned about - a line of your length should be able to perform quite well at 8Mb and be able to cope with a 6dB SNRM without any problems.
From what youve said about your socket it sounds like you have an LJU2 which dont have the test socket.
hmmm 6dB... are you using one of the older Home hubs by any chance?