Is anyone else who is on Fibre seeing a reduced downstream thoughput ?

[#1]

This is the second time on a Sunday  late afternoon /evening  that i have noticed this happen, in the past 4 weeks  whilst connected to the same GW  ptw-ag03.plus.net 
My downstream throughput  ranges from 15mbps to 25mbps less than it normally is, and latency whilst transferring data is noticeably increased, is this due to some kind of throttling of HTTP ?
Is anyone else seeing the same thing today ?
A normal speed test result http://www.thinkbroadband.com/speedtest/button/136958105995657325912.png
Speed tests that show Reduced throughput
http://www.thinkbroadband.com/speedtest/button/136958644727628449959.png
http://www.speedtest.net/result/2732893636.png

[#2]

Fine here getting 73-74mb all day

And jd's auto speedtester

[#3]

Still getting 40+ and 18 upload!!!   I'm lucky to get over 0.9 upload.pfft.

[#4]

The usual peak time jitter /loss of throughput or consistency of throughput, even the Think broadband quality meter shows a little packet loss when i utilise the downstream for speedtests ect, 
To me this is evidence of high utilisation somewhere, & why would it be worse on a Sunday ?

[#5]

Limiting of bursts is a "feature" of traffic management - its also a feature of traffic congestion on the network or an overloaded destination.

[#6]

fine all night

[#7]

I'm on Plusnet Essentials Fibre FTTC -  supposed to be Up to 40Mb speeds - server says my max achieveable is 38Mbs
When instillation was activated my best achieved was

but i've been having connection issues ever since - and especially noticed reduced speeds last weekend -
and today i am currently

[#8]

Yes i cab see a brief period of jitter on my and some other TBBQM graphs and again followed by a reduction in downstream throughput
  should be   It's hard to believe that there isn't a capacity issue somewhere, either that or this traffic prioritisation ( aka throttling ) is uber aggressive as it's affecting HTTP traffic  Either way something ain't right , oh BTW there will be some who are not affected this could  suggest things aren't being  or remaining  balanced properly over time

[#9]

Well i decided to Hop Gateways and on this other GW although the jitter is still evident on ping graphs (which would indicate that it's present on the return path) the low throughput issue is more or less resolved ,so is acceptable to me, certainly an improvement