For what it's worth, this is what I was getting this morning using
http://speedtester.bt.com/
IP profile for your line is - 5000 kbps
DSL connection rate: 448 kbps(UP-STREAM) 5888 kbps(DOWN-STREAM)
Actual IP throughput achieved during the test was - 4526 kbps
I get identical figures on my wired connection and my wireless connection upstairs.
Could not test last night, but usually during peak times this figure drops quite a bit. Don't know what it's like around 11pm though.
Hope this helps!