The Odyssey Pro headset turned up this morning.
A nice thing it is too. It is clear that the stack height is quite low in comparison to the STX unit alongside. Subtract the section that inserts into the frame and there's a few extra mm. Just enough to grip on! There's also a grub screw on one side to stop any movement, because it doesn't run a washer between the top nuts, which is another contribution towards its low stack.
My mate came over with a box of bits that he swapped with me. A pair of XT crank arms, XT rear mech, XT front mech and a lovely chainring I've been watching in his garage!
I'll need to clean them all a bit though.
I bought another XT lever from here, to match the one I had. Can't remember who from, but thanks anyway.
Also, my chainring bolts and Black aluminium bottle cage bolts arrived. You can see the chainring backs are Titanium and the fronts are genuine Pace items, and there's even a spare. The bottle cage bolts are for various applications on the frame, such as pannier mounts, bottle cage holes etc.