...I use newsgroups for downloads generally and they always fly at the full 3MB/sec or thereabouts
Very useful to know.
I'd expect p2p, torrents, etc. to be throttled with most ISPs.
Usenet is a tricky one because it tends to be related to an ISPs overall performance (rather than their protocol throttling).
What sort of usage are you doing each month?
Do you ever get into trouble with BT for going over their pretty vague FUP (i.e. quotes no upper limit at all; other than to say "the top 5% of users").
I know BT did have a terrible name if usage went over about 20-30GB (even on the unlimited package) but I find it hard to see how any ISP could justify that as a typical monthly allowance over a 40Mb fibre connection (especially given a 25.5Mb connection could download an entire 30GB monthly allowance in a little over 2.5 hours).
Ade
ADSL2+ with BE
DL Sync around 4.8Mbps
UL Sync 1088kbps
DG834GT with DGTeam firmware