Oh dear - OK, the article's good, but the speed tester is no different to about a dozen tools out there with the exception that there is no warning that the information is only as accurate as the response of the server at the other end of the test link.
Next, the comparison tool states that in my area Tiscali is offering the best deal - ah but then comes the rub, no they don't as they cannot guarantee the speed and there is no LLU service here anyway.
Really, I know what you are trying to do here but the bottom line is the same as I have been saying professionally and journalistically for years. If you don't own the infrastructure (ie: the physical cable and equipment between the premises (home) and the exchange), then you cannot guarantee or influence the speed of the service. Mobile is even worse as you have even more variables (handset, tariff, location, radial distance from cell, cellular traffic etc).
If you want to get a reliable service, then the only answer is to get it from the person who looks after and owns the cable and exchange equipment. I would also respectfully ask that any recommendations that include an LLU service state clearly that if a customer opts for this, they may be charged by BT to be reconnected at the end of their contract if the client wishes to go elsewhere.
This is a minefield and as I said at the outset this is a good idea, but too much emphasis is on the price and not enough on the many different issues that can cause the service to be slower than advertised.
SHARK!
For every positive action, there's an equal and opposite government plan.