Been through a heap of information on the Concorde models and I have narrowed this frame to either a Squadra or Prelude.
The Squadra was built from SLX or TSX tubing (same but different name?).
The Prelude is the only model that I have found specifically noting PRX tubing.
However, I have also read that PRX was also sometimes referred to as "new SLX" which has me again chasing my tail.

Those of you who have a Concorde, does it use a British or Italian threaded headset?