Issues with my FTTC Trial

[#1]

Message for Dave - apologies if this is not the correct method for notifying issues.
I've been on the trial for a few months now and overall I am very pleased with it.
I do however get some issues with performance.
Example 1.
Last night 20/12/2010 at about 11pm I tried to watch some Iplayer on my Ipod Touch and it constantly bufferred.  This happens fairly regularly.
Example 2
Watching Iplayer via the internet@tv function on my Samsung TV.  Frequently if I watch a program in HD it will keep stopping due to buffering - this is especially the case in the evening. Watching in SD very rarely has any issues.
Example 3
Watching Muzutv music videos again on the internet@tv function on my Samsung TV will frequently cause buffering (again usually in the evening).
I'm not sure if this is a throttling issue (perhaps related to the Plusnet product I have) but I would appreciate any feedback you have regarding what might be causing this.
Regards

[#2]

Hi Jetplan,
I've seen similar issues, but tends to be when I'm using a wireless connection when the PC's further away from the wireless router...  I've not seen buffering issues on a wired connection, or when I've got a 'strong' wireless connection.  I'm not familiar with Samsung Internet TV, but might be something similar if you're using a wireless dongle with it rather than a wired connection?
Cheers,
James

[#3]

Thanks for the reply James.
I'm pretty sure it's the broadband that is the issue.
My TV is connented to the router via ethernet cable (via power line adapters). I never have any problems streaming HD movies from my NAS drive to the TV and these are large files and are delivered over ethernet so I think my LAN is good.
Cheers,
Sean.

[#4]

 What accounts you guys have ?
 Plusnet, as Im sure others too, limit the bandwidth on certain activity, example even though my connection speed is
38mbps my connection to the PSN servers is limited to 2mbps on a value account.
I have recently upgraded to a Extra account hand have seen much better speeds to these kind of things.
Connections to iPlayer , youtube , gaming servers etc etc etc are all affected by this.
http://www.plus.net/support/broadband/speed_guide/download_speeds.shtml

[#5]

I was wondering if it might be my package but I'm also on a Plusnet Extra package and the table indicates I should be getting "line speed" for streaming.
My linespeed is 37Mb so I would hope this was enough to stream BBC Iplayer in HD. 
Thanks,
Sean.

[#6]

Even with my 38mbps I have never been able to stream BBC HD content to a 'watchable' level.