I've lost my trusty online graph that I could mentally apply adjustments to. I'm sure I downloaded it just in case this happened, but ....
Anyway, the attenuation suggests you should get a lot more than 11811kbps downstream. The upstream is reasonably good, as the maximum is around 1.3/1.4Mbps.
What's hitting you is the 11.9dB noise margin. On ADSL2+ I reckon each 3dB over the normal 6dB cost between 700 and 1200kbps.
If the connection was made late today, during dusk or later, I suggest taking the stats (and recording/storing them) any time between 10am and 4pm, then immediately do a single reconnection and take them again as soon as it has reconnected. Then we can see the result and compare the before and after.
We take it from there

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My broadband basic info/help site - www.robertos.me.uk |
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Connection - Plusnet UnLim Fibre (FTTC). Sync ~ 58.7/14.6Mbps @ 600m. -
BQM
"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
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Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.