Leave modem/router switched on - old wives' tale?

[#1]

Right, that bedroom extension wiring is a problem, old non-twisted pair standard, Can you see exactly where it's connected at the other end?
Is the cable from your plug in job, round or flat?

[#2]

OK, the experiment seems to be a success! The old bedroom extension has been removed and scrapped - this was good for roughly another 1Mb/s. For tidiness I've fitted a filtered front plate on the master socket instead of the stand alone microfilter. The DLM has been busy reconfiguring the line, and still does so occasionally. DSL speed is about 9Mb/s and download is consistently around 6.7Mb/s, an improvement of around 70%.
Many thanks to all who helped on this thread - I've learned a lot!
Link Information

Uptime: 1 day, 14:48:18
DSL Type: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 444 / 9,063
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 22.0 / 41.0
SN Margin (Up/Down) [dB]: 28.5 / 4.5
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 85 / 0
FEC Errors (Up/Down): 0 / 3,594,535
CRC Errors (Up/Down): 0 / 181
HEC Errors (Up/Down): 0 / 156

[#3]

That's certainly looking better, but I'd have expected a slightly higher sync speed. That said, the CRC errors are significantly better, in fact very good!
So how is the extension in the lounge now connected and where is the modem/router plugged in now?

[#4]

Thanks Anotherone. I'm happy with the sync rate, this being the fastest ADSL I've ever had (including 3 previous addresses).
A little rearrangement has enabled the modem to be plugged directly into the master socket's filtered front panel, with the extension just feeding the phone.
I've noticed some Openreach activity nearby in recent days - it would be ironic if after going to all this trouble I get the choice of fibre ...

[#5]

Glad that's worked out then. Hope the Openreach works don't cause you any dropped connections 

[#6]

i always turn my router off, when not in use, since being told by plusnet to log into my router and click disconnect first,(before turning pc/router off) ive had no probs whatsoever, speeds are constant

[#7]

Then you will be lucky if that remains the case as I see you've been having some problems and had to ask for an SNR reset. For people on longer lines than you, the time that they switch on could be critical especially on 20CN, if it happens to be in daylight, they may be fine. Logging into the modem/router and clicking Disconnect before power down helps to prevent DLM from thinking you might have a (worse) dropping connection, but it will make no difference whatsoever to the sync speed you can achieve at switch on - this is what is critical to maintaining a good profile on longer lines.