This genuine Roto H600 genuine gearbox is available with a single spindle and a 35mm backset.
Operation: Lift lever
Latch reversal: Locate the small hole above the latch and insert an 2mm allen key which should go down at a slight angle, push down on the allen key and at the same time pull the latch out, reverse latch and reinsert, push latch right in and test to ensure it is connected properly
