well, tried it both yesterday and today and tried the test in Opera,Firefox and IE, it's not working for me.
Are there any other speed test sites that i could use to display details of my connection?
The BT speedtester can be erratic, sometimes working , sometimes not working.
There are other speedtests that you can use, how accurate they are i will leave for others to answer.
These other speedtests will not show your profile, and if you are looking to speak to support about your speeds etc, they will need BT's test .
 BT speedtester working here @ 20.46
If using speedtest.net make sure you select either the London (Namesco) server or the Paris one as these are the most consistant and reliable ones.