What are these hexagonal things under the Concorde's neck? The Concorde had a pair of dark-coloured hexagons under each of its forward boarding doors, as seen in this picture (showing the hexagons on the left side of the Concorde's neck):


British Airways Concorde, Pictured by LondonAirTravel at the BA Engineering Base, London Heathrow (link)

What are they, and what purpose do they serve?  They obviously aren't passenger or crew windows, and they're far too big to be static ports yet far too small to be cargo doors - some sort of maintenance access panel, maybe?
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  This is the side loading door. Under this door are the static pressure
  panels that provide data to the Air Data Computers. They have been
  painted over now.


Here is a nice close up image 



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