Ive had BT Infinity ever since it became available in my area. Speedtest has never been above 28Mbps and more normally only around 20Mbps. I was told this is because although as the crow flies I'm only about 400m from the FTTC cab I'm actually on a wiring route of over 2Km. So I have accepted this.
My immediate next door neighbour has just had the same BT Infinity (latest router of course) installed for the 1st time and in the 1st day getting 37Mbps - this should improve as it settles down.
It would seem unlikely that he's on a different copper wiring route to me - possible I guess - so any other explanations?

How are your connecting to the web? wireless or with a cable

Both direct ethernet (Mac) and wireless (iPhone & iPad).

As you are connected by cable on your Mac that rules out wireless issues so it could be a line fault or a problem with the hub

Give your neighbours internet a week or so from the install date to settle down and see what speeds they get if they continue to get more than you I would contact BT and explain what they get and what you get, they may suggest a replacement hub or they may have to get an engineer to look into it

Have you tried the BT Wholesale speed test? http://speedtest.btwholesale.com/

Thanks Gavin, yes tried all advice on BT website including their line test. Will certainly be keeping tabs on them to see what they get!

Go on the BT page, contact us and search for complaints, send them an email, you will get a much faster resonse
Out of interest if you go on a competitors page and to a line check, what speeds does it say you should get ? Thats what you should be aiming for