Today's Progress:

Because of the "twisting" forces on the steering column I made a pinch-bolt sleeve and welded it to the intermediate tube, so it can now be done up very tightly with an M6 bolt.

It appears to be very solid (I am happy to say), so now I will adjust the angles of the MBB relative to the headset clamp and the required angles to position the handlebars optimally.

It is coming along OK I think.