minimum download speed for IPTV

Hi I originally made a posting concerning the legality of Watch British TV Abroad now I have some concerns about the service which I now use and its minimum download speed. In their literature they say that you need at least 2 MB download speed for it to work. There is a test you can do which indicates that my download speed is well over 6 MB but I often have trouble with it and hoped that someone out there might be able to give some advice. The picture often freezes and in particular during the night. I contacted the service providers and they said that I had a problem with my internet (which is strange given the 6 MB download speed). I thought perhaps there was a problem at their end with the server when peak demand resulted in freeezing of picture. Someone told me that even though the test might say I have download speed of 6 MB on occassions it will drop to 1 MB which might explain the freezing of picture. He told me that these download test sites basically place a file on my computer to see how long it takes to download and then gives an average download speed for that action. Could it therefore be the case that indeed it does drop below 2 MB and thus explain the freezing. Or are the service providers trying to pull the wool over my eyes. Is there another test I can do to check this. Help PLEASE.