This information is all there if you go back over the last few pages of the thread. The public investigation of the Dulles incident would have been handled by the NTSB, not the BEA. In essence, the BEA were simply backing up in private what the NTSB determined in public.
The fix was a device which detected improper tyre inflation (the root cause of the Dulles incident) and fed that information back to the flight deck. The damage to the fuel tank was external and not sufficient to cause fire, very different from the F-BTSC damage which was caused by compression of the tank causing it to burst outwards. This was unforeseen by all. The Kevlar lining was designed to prevent that kind of damage, not the kind that occurred at Dulles.
In fact the Kevlar lining was not strictly required, providing instead a level of redundancy - the post-2000 tyre design would have been enough on its own to get the AOC reinstated.