There seems to be sometimes a delay between broadband being available in an area and the specific lines being checked to see if they are suitable. So while there is broadband and you may be within the 3km (?right distance) limit of the exchange, unless an engineer actually tests your line for broadband, the database they use will show that your line is not broadband suitable.
Netsource used to have a site that showed the last date the line was actually tested, but that is no longer there now they are part of magnet. Does anyone know of a site that has the date of the last line check on it?