Dave Rado wrote on Nov 8^th, 2013 at 2:16pm:

You've obviously not looked very far as BT Phonebook lists the number 01206 581005.... 

Dave Rado wrote on Nov 8^th, 2013 at 2:46pm:

I think the thing you've got to consider is that when a staff member says there isn't an alterative number that they are saying that under company policy the number customers call is the 0845 one - this effectively being the "front door" as far as telephone contact goes.

BT Phonebook is usually the first place I look when seeking an alternative because sometimes it does offer one. Don't form any preconceptions that it definitely won't be listed; you can, of course, hold an opinion that it is unlikely.