Indeed. As I say though, there is no technology or network side change that should cause such a symptom, nor are there signs of congestion showing on your connection so I suspect the problem lies elsewhere.
There *are* cases I know of when maxing out a router can cause certain things to slow down lower than they were before, though it's a long shot.
Can I suggest directly connecting your PC to the modem and connecting that way to see if there's any difference? You'll need to set up a PPPoE connection in Windows Network centre with
bthomehub@btbroadband.com as the username.