Not Delhi! They wouldn't even know what we are talking about.

You need to read and understand the BT IP Profile, noise margin and Troubleshooting pages on my website. The only possible immediate change from connecting to the test socket is the connection speed or occasionally the attenuation. The noise margin always resets to whatever the exchange equipment specify, and we could do with knowing what it is immediately after a reconnection.

Sync speed should always be higher when you connect during daylight that dawn, dusk, night. But is it still connected at that 192kbps? If so, do a single reconnect now and post the stats straight after.

Did the BT test again and....

Download speedachieved during the test was - 4025 Kbps
For your connection, the acceptable range of speeds is 600-7150 Kbps.
Additional Information:
Your DSL Connection Rate :5632 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
IP Profile for your line is - 4500 Kbps

[censored]?

The IP profile will not improve immediately, it takes between an hour and five days to improve.

Because the swing was so large, then it has improved the IP Profile fast for you. Is this with the modem in the test socket?

I would suggest running the modem from the test socket for a few days, and see how things are. i.e. does the IP profile stay at around this 4500 figure, rather than up or down to 350Kbps. If yes then the wiring in your property is the problem and NOT talktalk

Download speedachieved during the test was - 4025 Kbps
IP Profile for your line is - 4500 Kbps

pretty good for the profile.

Line Mode G.dmt Line State Show Time
Latency Type Interleave Line Up Time Duration 00:00:12:53
Line Coding Trellis On Line Up Count 2


Statistics Downstream Upstream
Line Rate 6048 Kbps 448 Kbps
Attainable Line Rate 6592 Kbps 1096 Kbps
Noise Margin 11.8 dB 21.0 dB
Line Attenuation 28.5 dB 22.0 dB
Output Power 12.3 dBm 19.8 dBm

the max attainable from the router is more. I connected it to the BT master/test socket thing last night so will leave it in that for now and see what happens tonight.