In the 1930's the Swiss motorcycle factory CONDOR used Rudge gearboxes , then they made there own version , changing main and layshaft position , including gearchange mechanism in the case . This is what Rudge could have done
fullsize foto is a Condor racer with original Rudge box , closeup is a Condor box in a works hillclimb racer

Weiter entwicklung von Condor , Schweiz
Rudge patent aber mit schaltautomat im gehäuse , metrische dimension und umgekehrte antriebs und nebenwelle