welcome to the forum
there could bve many reasons - how is the tv connected to internet wireless or wired?
in order for the forum members to help please can you post the adsl stats from your router may need to 'show detail' to get all stats (if hub enter 192.168.1.254 in your browser and navigate to adsl or use a-z, if netgear enter 192.168.0.1) and run btspeedtester (MAC users may have problems) http://speedtester.bt.com or http://bt.custhelp.com/app/answers/detail/a_id/9354/c/346,4740,5520 and post the results .
are you connected directly to the NTE5 master or test socket or to somewhere else? Is the master the only phone socket in your home?
Have you tried the quiet line test? - dial 17070 option 2 - should hear nothing - best done with a corded phone. if cordless phone you may hear a 'dull hum' which is normal
Someone may then be able to offer help/assistance/suggestions to your problem
try it out of peak hours 1600-1200, i have the same problem as do many others. was trying to watch the non hd version of topgear tonight and it bufferd a few times.
seems bt's either having issues or someones playing silly buggers with what gets capped (shapped) as netflix is just as bad.
i assumed they ment download and put upload by mistake.
as for iplayer being shaped or not i guess its open to interpretation because bt admit they do limit traffic across the network at peak times, but claim they dont shape anything 😛