I have found the most reliable test for upload to be http://myspeed.visualware.com/index.php . Recently, their download estimates have been terrible. The BT retail tester gives the worst upload estimates; under certain conditions I was getting around 3Mbps from it, when visualware or real uploads (ftp to SquirrelSave) were at 17Mbps.
I was getting strange messages from that site regarding "your trial is over please purchase" - so stopped using.
Odd. I used to use the same test at a different address; which had a more convenient entry direct to the test but stopped working. The error might have been 'trial expired', I can't remember. It was around the time of that change that I also found it started giving very low download estimates. But I haven't had any problems actually getting the new one to run.
With the new address: I initially see a map of the world, click on the UK and get a map of UK, and click on Maidenhead (usually, better results for me than London). That then gets me to the test page where I click on 'Click to start test'. With the old address, I went straight to the page with 'Click to start test'.
Moved (with trepidation) to BT Infinity 2 for upload speed. Happy BE user for several years.
Edited by StephenTodd (Thu 06-Dec-12 09:43:52)