As your results demonstrate, many speedtests are not accurate or reliable, particularly for 20Mb connections.
That's why Tech Support recommend you do four simultaneous file downloads from UK servers to test the real speed.
Have a read of
"How can I test that I am downloading at my correct speed?" on Annie's FAQ for guidance?
If that shows your connection is still slow, it's probably worth doing all the tests (q5, q6 and q7) and reposting the results to the newsgroup to help TS identify the problem.