I am in the process of buying a house in london, and the surveyor has noticed a small crack (1mm-2mm) in the external brickwork - no visible crack on the inside of the house (although wallpapered). This was a full structural survey. He has mentioned that this is not serious at all. I have also sent a photo to a structual surveyor (friend of a friend) and he also says nothing to worry about - thermal crack etc. I would be grateful if you have any comments before the the sale progresses further.