Possible broadband speed issues

[#1]

I've got incredibly slow speeds this evening (I have a fault open plus another thread elsewhere on this)
Pings tracerts and nslookups on various of the obvious sites (bbc, google, (and bbmax as that's where I'm speedtesting)) are all fine, but browsing is awful, and  a BBMAX speedtest showed 144 down 39 up, yet a BT speedtest is giving 5567 down .
If this was local congestion wouldn;t the BT speedtest be affected too?

[#2]

I just tried to call in my fault but there is a 15 minute wait !!!!!!!!!!!!

[#3]

Finally managed to log a call.
It took me almost have an hour just to complete the detailed questions (Windows version, modem type etc) due to ths slow connection !!!