slow fibre speeds and responsiveness

[#1]

Hello
We moved house a few weeks ago and took our plusnet with us. On the phone we were told we should be able to get 45mbps download. When the engineer came and set everything up he said we should be able to get 55mbps+. However, we're barely getting half of that at about 25mbps (this is connected by ethernet not wifi). In addition to the slow speeds most websites are very unresponsive taking up to a couple of minutes to load successfully, though this is intermittent.
I did the test at http://speedtest.btwholesale.com/ and that records 25mbps down, 16 mbps up and a latency of 19ms. Running the full test at http://www.speedtest.btwholesale.com/PerformanceTesterWS/diagnostics.do seems to imply that we should be getting more then we are http://i.imgur.com/i2FS98L.png.
Could anyone offer any guidance, please.

[#2]

Hi gibbonsss,
Sorry to hear speeds are below par and thanks a lot for confirming you're connected over ethernet.
I've performed a full set of diagnostics which don't actually show an obvious cause for the issue. Please head over to http://faults.plus.net to raise this with us.