Question regarding my line stats

Being quite the novice with line stats, noise margins etc. I wondered if someone could offer some advice if I should be expected to receive faster upload/download rates based on the router stats below. Or if they are to be expected.

Some background on my setup: I have BT Infinity 1 unlimited package. Setup is very straight forward: Line comes in to the home from overhead street pole. Inside the property the external BT black drop-wire connects to a small junction box. From there 1 metre of CW1308 cable connects to the master socket which is a NTE5c mk.2 and a VDSL mk.4 faceplate. From the faceplate I have a 1 metre cat 6 cable that connects in to my BT Smart Hub. Cables, junction box and faceplate are all less than 1 year old.

The line is stable with the router often re-sync'ing once every 20 - 30 days, so I can't complain about that. But I wondered with the following router stats, should I be expected to receive higher speeds, or are these pretty standard for the line quality that I have?

BT Smart Hub stats:
Data rate: 6.21 Mbps / 40.41 Mbps
Maximum data rate: 6298 / 46448
Noise margin: 6.1 dB / 5 dB
Line attenuation: 22.6 dB
Latency type: Fast Path

The noise margin for the right value fluctuates between 5 and a max of 6.2dB throughout the day. The above sync speeds are pretty consistent with the BT DSL checker also. For reference the DSL line checker last check was before I replaced all internal cables and faceplate from very old internal wiring.

It is about right or maybe a little low ... The max rates continually vary and if you watch closely you could see that go up and down by 2, 3, 4 Mbps. There sounds as though there is not much you can do or tweak - just keep any noise sources away from the line and modem.

Looks fine to me, might go slightly faster if stable enough.

When I perform a BT quiet line test there's a constant low level hiss, a bit like putting a sea shell to your ear, however not as loud. This noise is exactly the same audio level when the router is plugged in and the phone line is connected to the VDSL faceplate and even when the phone is connected directly to the test socket behind the faceplate with no router connected. I have tested with a 2nd non-branded corded phone and I hear a level of noise on that too. The noise sounds a little different on the 2nd phone with a very faint high pitched tone (that could be the cheap phone and not the line?). Also when performing the quiet line test whilst I powered on the router, I could hear various tones, beeps and screeches from the router sync'ing with the exchange. This was with the router and phone line connected to the VDSL faceplate. Is this normal to hear this on the voice line? The junction box, white cable and master socket / face plate are all less than 2 years old. During my tests I have tested with a different VDSL faceplate with the same results.

Edited by deleted (Sat 30-Dec-17 14:00:55)

I've gotten to the bottom of it. By using an unlocked Huawei HG612 modem I can see that there is 8ms of interleaving applied to the downstream. G.INP is not enabled either. I'm on an ECI cabinet and have read about the struggles with G.INP. Anyone know if these issues are now resolved, or are they still ongoing?