This is probably a RHD thing, today I went to test fit the steering column and firewall and noticed the slot for the carb adjusting rod didn't line up with the support bracket. Compared it to the 27 Tourer and the steering columns are different.
At some point someone has drilled extra holes in both brackets and the steering column on the Tourer.
The Tourer is currently running a Vaporizer but it did have an NH. Is the wider slot meant for a Vaporizer? It seems to line up best.