@Teresa45 Sky test's the speed direct to the hub so the 54Mb/s could well be correct, speedtest.net test's the speed to your testing device with everything else going on in a shared network so that 20Mb/s may well be correct if someting else is pulling bandwidth at the same time say watching a streaming HD TV device....
The service checker will show you what sky is seeing daily to your Hub, use the Broadband and > to expand and see, post 4 on the link gives you the idea what to look at with that....
Service Checker bars
https://helpforum.sky.com/t5/Broadband/Broadband-speeds-reported-versus-actual/td-p/5171393
https://www.sky.com/servicechecker
