Thanks delta rider for the link to a previous forum discussion. Sounds like there are lots of different opinions, not helped by the inconsistencies in Honda manuals and schematics.
I am reasonably sure that the torque arm should not be tight at the brake end, and it would seem logical to me to have the rubber washer between the aluminium brake case and the steel torque arm, so this is going to be my set up when I get the new t-bolt from David silver.