Let me try and clarify a few things by reviewing a few of the variables here....
1) Was the problem with the spacer a known item that was MEL'd, a maintenance mistake that was not caught or a known problem not yet fixed?
2) My understanding is that the last information from the tower to the Concorde was an 8 knot tailwind...is this correct
3) The Concorde used the extended portion of the runway whose surface was not properly finished and very rough
4) An unknown amount of luggage was not properly logged for weight calculations
5) The plane based on documented weight at push off was over its max operating limit and relying on fuel burn during taxi to be legal at takeoff