Have you tried a different modem?

He'll be using the standard issue Sky router I suspect ?

My thoughts exactly. never had problems like this on adsl 8m. So that ruled out interference for me.

never had problems like this on adsl 8m.

I'm guessing the only thing to changed since is your service now uses Sky's kit in the exchange, and their router.

I'd be inclined to get a HG612 from Flea Bay and set up DSLStats and MyDSLWebStats for 24*7 monitoring.

the second time it happened i tried my old tp link router for 5 mins but disconnected once while connected to it so just threw the sky hub back in, 5 mins aint a great test lol.. Might throw it back in and leave it a day or so to see what comes up. it also has the ability to record its own stats so it might be easier for you guys to diagnose with some proper info if the problem still occurs with another router.

Pretty much yes.. Plus the 2nd adsl line.. I got my 2nd adsl line around the same time i switched to sky to lessen the load on the sky one as the family are heavy netflix users so thought a 2nd line would fix the problem with the slow net while streaming. I don't think that is the issue but called SSE up today to cancel and terminate my service to see if that fixes the problem.

Does not rule out interference totally, the dipping SNR suggests something is messing with the signal somewhere and as the old up to 8 Mbps service only uses about half the upstream capability available there was lots of room for surviving noise in the frequency bands the upload uses.

I've just plugged in my old router and there have been no disconnects so far, have had it on for about 30 mins so keeping fingers crossed. It looks to me also this router connected increases the snr for both upstream and down including line attenuation, maybe it is a stability issue.. i'll keep an eye on it.

Upstream Downstream
Current Rate (Kbps) 796 7484
Max Rate (Kbps) 905 7140
SNR Margin (dB) 9.3 4.8
Line Attenuation (dB) 23.1 47.3
Errors (Pkts) 0 0

Sky used to be fairly good about users requesting tweaks to their DLM, so if upload is not crucial they could get the DLM tweaked to give lower upload e.g. 550 Kbps

Another option is to use a router that allows the user to tweak the ADSL2+ target margins/stability, though cannot recall if this does work on the Sky DSLAM