Advice from the experts...worth getting OR out again to look at FTTC install?

[#1]

Hi everybody,
I was hoping to canvass the opinions of the resident experts as to whether it is worth getting OR out again for FTTC speed issues. I don’t want to spend another day at home if the chance of speed improvements is small. I also ought to say that I appreciate my FTTC speed is significantly better than some of those on ADSL, so don’t mean to moan.
My FTTC is synced at ~24, and has been since the install last week. The BT speed checker suggests that I should be able to get 33.9/6.5. I live 750m away from the cabinet. Due to error seconds on the line, and a below predicted sync rate, PN expeditiously arranged for an OR engineer to come out. In the end, two engineers came on the same day (only one underground trained). One, an apprentice, suggested from his testing that there may be an underground fault 81 feet away, but he was unable to investigate other than confirming that a full 40/2 was possible at the cabinet and doing a profile reset (causing no improvement). The second engineer replaced my external wiring and junction box (making no difference – it was just old), and changed some of the crimp connectors at the cabinet, but (as far as I can tell) didn’t lift any manholes (my cable is fully underground). He declared the line to be healthy and stated that the sync speed was just ‘one of those things’. Both engineers spent quite a while doing tests with their JDSU etc.  I’ve noticed no noise on the quietline test.
I’ve interrogated the OR modem, and attach the figures below. It strikes me that the predominant finding is very high attenuation figures, although I’m clearly not an expert. I suspect (although don’t categorically know) that some of my line may be aluminium, which may be a factor.
Max: Upstream rate = 3645 Kbps, Downstream rate = 24464 Kbps
Path: 0, Upstream rate = 1999 Kbps, Downstream rate = 24700 Kbps
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 3645 kbps 24464 kbps
Actual Aggregate Tx Power: 5.9 dBm 10.5 dBm
===============================================
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 10.2 59.0 67.0 N/A 23.6 67.6 0.1
Signal Attenuation(dB): 15.9 58.1 N/A N/A 23.6 67.6 N/A
SNR Margin(dB): 11.0 10.8 N/A N/A 5.7 0.0 N/A
TX Power(dBm): -4.3 5.4 N/A N/A 9.6 3.1 N/A

The results of PN testing are below;
Current and Last 15 Minute Bin Performance
Last Traffic Count(Upto 15 mins) Current Traffic Count(Upto 15 mins)
Ingress Code Violation 2 0
Egress Code Violation 43 25
Errored Seconds 34 21
Severely Errored Seconds 0 0
Unavailable Seconds 0 0

My question is whether it’s worth getting OR out again? PN have been very proactive in offering to (due to the ongoing sync speed and error seconds). I have a suspicion that this all may be due to possible underground aluminium, but I have no idea whether there are other equally likely explanations. Essentially, would the experts bother with OR or just make do?
Thanks very much!
John

[#2]

It's up to you, however I'd like to try something first. I've made a change to the connection profile on your account. could you powercylcle your modem and let me know if that changes anything?

[#3]

Thanks, Adam. I'll cycle the modem when I get home tonight and let you know.

[#4]

Hi Adam,
I power cycled the router and modem, but can't see that things have significantly changed. It's still synced at ~24.
Would any of the resident experts suggest that a further OR visit might pick up something rectifiable?
Thanks to all.

[#5]

For the distance, those attenuation figures do indeed look high - if they were for copper. Likewise, 750 metres ought to give better results - but again with copper.
To give you comparisons, here's what I got on my current line, around 450 metres of copper:

       VDSL Port Details       Upstream        Downstream
Attainable Net Data Rate:      27145 kbps         90304 kbps
Actual Aggregate Tx Power:        6.9 dBm          13.0 dBm
============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3
  Line Attenuation(dB):  4.3     21.5    31.4     N/A    11.3    27.0    40.9
Signal Attenuation(dB):  10.8    20.5    29.9     N/A    11.3    27.0    40.9
        SNR Margin(dB):  17.4    17.4    17.4     N/A    20.9    20.9    21.4
         TX Power(dBm): -3.9    -24.8    6.4      N/A    9.7     8.0     6.4

On my previous line, which was around 600-650 metres of copper, and didn't quite behave perfectly (some packet loss until interleaving was turned on by DLM):

       VDSL Port Details       Upstream        Downstream
Attainable Net Data Rate:      16464 kbps         59076 kbps
Actual Aggregate Tx Power:        6.6 dBm          12.3 dBm
============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3
  Line Attenuation(dB):  5.4     27.7    40.8     N/A    14.1    34.4    53.1
Signal Attenuation(dB):  11.5    27.2    40.1     N/A    14.1    34.4    53.1
        SNR Margin(dB):  11.3    11.2    11.1     N/A    9.3     11.0    9.9
         TX Power(dBm): -3.7    -16.8    6.3      N/A    8.5     7.9     5.4

When I've compared to other sets of figures, the attenuation does appear to go up linearly with distance. If you are 750 metres, then that would suggest you ought to have attenuation of around 17dB in D1, 42dB in D2 and 65dB in D3. That means D3 would be getting close to unusable, but the other two ought to be better than they are.
Finally, there is another Plusnet user @BaldEagle_1 who has been having speed woes, and got around the same speeds from, IIRC, a longer line. I'll see if I can get hime to add his figures here too...