Sadly, I cannot see £120m being anywhere near enough. I recall my time dealing with the same generation of military aircraft, engines, avionics etc and the cost of re-establishing the engineering support and production facilities to produce necessary parts would be horrendous. And then you’d have the certification (and insurance) issues. Would the CAA, BEA and FAA be prepared to play ball?
That said, I’d be prepared to pay a not inconsiderable sum for what would be my first (and probably last) Concorde trip.