Brembo have made a brake upgrade for the Tbird and Adventurer for quite a while. The Thruxton uses the same brake as the TBird (albeit with a floating rotor) so that kit should work just fine. I suspect that's what you are looking at.
Mick-thats what I have been trying to research - knowing that 2pot nissin on my thrux - is used on a slew of bikes in the world - there has to be a four pot replacement - any idea on where I can find the brake upgrade you talked about on the T-bird. I'd like to check it out to see if it might work. TIA JCW