Not sure how far I am from the exchange but I do know that the line has had a fault on it since Aug 2004 which BT needed to come in the building to get fixed...and I've never been here. Having said that, it was more a voice problem - strange interferance.
Working on the basis that I live in the town (Cheltenham) centre I'm guessing the exchange isn't far away - then again nor is GCHQ!
I expect this was a 'special' deal to keep existing customers. I would still choose PIPEX as a new customer however - the price isn't significantly more than anyone else and it is generally excellent service.