Thanks cosmo.
As to the alpha the BEA traces show it hovering about 18 to 19 until just before control was lost when it went up to 25 and platformed briefly before coming steeply down. Without knowing the sensor/recorder type it looks to me as if the short platform could be an "on the stops" indication that may be hiding a momentary higher peak value that could have been 28ish. But that would be quite academic at that point in the flight.
I believe that the Concorde was expected to have a pitch up departure mode at about 25, but do not know that for sure. Again all academic as I would opine that it did not have anything like the thrust to hold speed at such an alpha, even with four engines, at least not at takeoff weights.
The guys who fly it (and the sim chaps) would know all this stuff for sure, but one can see why they are not wishing to get involved in such a chat as this.
Regards
John