XBOX Live latency

[#1]

Hi,
Over the last few weeks I have noticed really bad lag while gaming (various different Call Of Duty games), showing red or yellow bars.
My connection is ok, as I am getting 4.5-6.5meg on different speedtest sites and ping to another ISP server is a steady 40ms. I am on a up to 8meg connection (not LLU).
The problem isn't my xbox either as I have just bought a new one and it's the same on both (connected via ethernet). So, is this just a problem then with Plusnet bandwidth shaping?
Thanks,
Simon
Just to add to that, the problem only happens in the evenings so again that points to a Plusnet issue.
Unlikely to be a XBL issue as it is usually only me in the lobby at the time with the red/yellow bars.

[#2]

Just spoken to "support" about it and they said there is no issue on their network and no one has complained about it - obviously they don't read the forums!
The only option given was to pay more money for an upgrade which would apparently resolve something that isn't a problem. 
Great work there plusnet. 

[#3]

well they are lying about people complaining about it.
I gave up in the end mate.

[#4]

how late in the evening do you notice and have you tried limiting matchmaking to local? I notice, in the evenings, after about 10:00pm you end up playing mostly americans which can cause ridiculous lag cos they're so far away. I find searching for local lobbies fixes this issue

[#5]

I usually play any time between 7pm and midnight and it can be bad at any time (most of the time). Fine during the day though when I get a day off work and play during the day.
I have finally had a reply from Plusnet though after complaining:
"Although we are not sure where this problem is originating, we are aware that there is a potential issue."
So hopefully they will be able to get this sorted although it would seem the Ellacoyas would be a good place to start looking!