ISP is Virgin Media "up to 8mbps" over BT landline - which is the real limiter - Airport from Netgear.....
Best of three tests using Speakeasy was Seattle at 1936 download, Washington upload at 375; using
Speedtest.net:: Maidenhead (near London) 1524 download, 379 upload; Napier, New Zealand 1255 download, 332 upload; Seattle 1593 download, 369 upload.
I guess different organisations use slightly different criteria and set-ups for their tests, but it's curious the best results I got on both were through Seattle. All tests run at about 17.20-17.30 UK time.
As they have a European server you may well get a better measurement of your download speed.
As you are a "Beardy Weirdy" customer you may also have access to the Blueyonder FTP server. Try downloading a large file from there as that will also give you an idea of your "REAL" download speed. No ISP can guarantee speeds outside their own part of the network. That's why peoples results vary so much.