This topic was covered on one of Sky's digital channels recently (Concorde-Anatomy of a Disaster or some similar title.) It alleged that the 747 with President Chirac onboard was at a holding point roughly at the Concordes rotation point. It also alleged the wheel failure was nothing to do with "that" piece of metal on the runway, but by a missing wheel spacer (later found in a maintenance hangar) that caused severe oscilations of the wheel on the take-off run which subsequently failed way before the location of the metal FOD. It also covered the overweight condition due to excess fuel and baggage.
Again, this is not my opinion, but just reporting what the programme covered!!