Unfortunately you need a login to be able to use it, by the looks of it.
I just entered my phone number and it seemed to work fine.
http://www.dslchecker.bt.com/adsl/totl.input
Hmm...the first time I accessed the site, I'd Googled "tags on the line"...and it looks like the first hit contains someone's login details. As the login screen has a warning about unathorised access, it's probably better not to access it....
It gets my MTBE pretty accurate.0 ES everyday on the downstream, MTBE is 86385.Upstream MTBE doesn't match any day of the past 7 days.It matches 11am yesterday till 11am today