Thank you everyone for your replies. Here are my updates:
I did a test on the BT wholesale site. It gave me 31.64 download, 8.63 upload, ping latency 40.13. This is with laptop connected by Ethernet to the router with everything else turned off. I clicked on further diagnostics, entered my phone number and clicked for the diagnostics but it says: "Your speed test has completed and the results are shown above, however during the test an error occurred while trying to retrieve additional details regarding your service. As a result we are unable to determine if the speed you received during the test is acceptable for your service." So I can't give you my IP profile.
I did a speed test here (which is what I was doing before). This is the latest result, again downstairs but using wireless and with my laptop right next to the router:
The modem was brought by the BT engineer and the router came in the post from Plusnet. The router model is TG582n Technicolour. Not sure what the modem model is but the back of it says B-FOCuS Type 1B. I have moved the router up to the window sill, a few feet above the modem, which is on a little table in the hallway. This has meant that the speeds upstairs have improved from 10Mbps to the 13-24Mbps range, which I appreciate. My laptop is about 3 years old (Win7, 4Mb RAM).
Would appreciate your further thoughts, particularly about why I can't get an IP profile.
Edited by greenwich (Wed 27-Nov-13 08:27:39)