by Victor Bryant
Alan, Brian, Colin, David and Ed have the surnames Smith, Jones, Rogers, Mason and Hall, but not in this order.
In a queue, reading from the front Brian, Mr Smith and Ed are in order (but not necessarily adjacent) and this is also true for Mr Jones, Colin, Dave and Mr Hall. Mr Mason’s two neighbours are Alan and Mr Rogers.
If you knew Alan’s surname you could work out their surnames and their queue positions.
What is Alan’s surname and his position in the queue?