It is a VAR tool, I think all the tools are.

Looking again at the head tube facing tool I am sure the two guide pieces either side of the cutter are for 1 " and 1 1 /8 inch and you just fit the one you need. The worn 1 " one was used by the previous owner.

If I had the reamer cutter in place it would all fit together the same as Andrews photo, but without it, it needs the second guide piece to make it all lock up tight.

Good idea with the shims thankyou Steve.

Looking at reamers online they seem to come in 33.8 33.9 and 40.0. Does anyone know which I need for a Hope Headset?