well according to that your maximum speed is 27mbps, so that is the most you can expect, you test result is rather low though so you may still be connected by wireless, when you plug the cable in you have to turn wirless off or it wont connect. you cannot run annother one of those for an hour, but can you ensure that wirless is completely off then try speedtest.net again
So when I plug the ethernet cable in I must press the wireless button on the back of the home hub? The engineer told me that I should get 38mbps though, but I'm not sure if he meant I should get that speed through an ethernet cable or through wireless connection. Am I only expected to get 27mbps through wireless is that what you're saying?
not much help, but exactly the same thing happened with me. I was getting 36.5 down (ip profile 38) for a month. Then it dropped to 27. Phoned BT, got 2 engineers out, said no problems or dropouts with the line, no problems with the exchange, so nothing they could do and that I should live with it.
Then it went down to 18... and yesterday, went off altogether. Still off now. BUT - I unplugged the while openreach modem for ten mins this morning, and when I plugged it back in (and the connection magically connected) I was getting a speed of 36.5 again. Then an hour later it went off again... gah!
BUT - I suspect that these dramatic speed drops are due to faulty Openreach modems/buggy firmware, rather than physical connection problems. I am waiting for an engineer tommorow to switch modems and see if it fixes my problem.
So... try switching off (at the wall) the white Openreach modem for ten minutes, let it cool down and reset, and then try see if that helps any.