Hope this is wrong but there are discussion over at thinkbroadband suggesting that the peak hours will change in January.
http://bbs.adslguide.org.uk/showthreaded.php?Cat=0&Board=entanet&Number=3526519&page=0&view=expanded&sb=5&o=0&fpart=
http://bbs.adslguide.org.uk/showthreaded.php?Cat=0&Board=entanet&Number=3526519&page=0&view=expanded&sb=5&o=0&fpart=