I got a similar reply and asked for an internal review and the head of their Telephone systems stated that a geographical number didn't exist.
I can't be certain this is true or not as it's possible that some systems using VoIP which wouldn't have geographical numbers but it's my understanding that BT's system doesn't yet support VoIP fully.
I decided that without proof that a geographical existed and the fact that referring it to the ICO would mean a wait of nearly 12months due to a backlog.
My reply from the head of the their telephone systems can be found
here.
To be honest, I do believe that they will use the new 03x numbers once they are fully available but this isn't until early 2007 (I think). Therefore, I don't think it's worth doing anything further because you'll get the same response as me and that means referring it to the ICO which will add another year (nearly) on top of it and by this time (ie in a few months time), they'll most likely be using 03x numbers anyhow.