If you plug a corded phone (£5-7 from many places) into the test socket and dial 17070 then take option two, (it's called the Quiet Line Test), the line should be just that. Quiet. Any crackles and buzzes suggest a fault.
The test socket is the one revealed when you remove the master socket faceplate. Be careful when removing it as any extensions will be wired to it. Unless the engineer fitted one of the bulky new filter plates that have the broadband socket at the top and the normal faceplate at the bottom. If you have one of those then carefully unplug that too.
If you have a noisy line, then report that to whoever you pay line rental to. Do not mention the broadband even if it's the same supplier!
Once that is fixed your broadband speed should improve.
The indispensable man or woman passes from the scene, and what happens next is more or less the same thing as was happening before.
My broadband basic info/help site - www.robertos.me.uk.
Domains, site and mail hosting - Tsohost
Connection - Plusnet
UnLim Fibre (FTTC). Sync 57676/14040kbps @ 600m. - BQM