The SR engines had either a manual reverse gear OR the LH150 hydraulic gearbox. The LH150 box was more common in canal boats.
Both usually had separate reduction boxes on the back.
I assume that most (if not all) SR's WITHOUT the raised hand starting option, would have left hand props. I hope the following makes sense:
Standing at the front of the engine and looking towards the stern, the starting handle fits on the front of the camshaft which rotates clockwise.
The camshaft is gear driven from the crankshaft, so the crankshaft turns anti-clockwise.
The reduction gearbox is basically just 2 gears, so the rotation is changed to clockwise (again viewed from the front).
HTH, I have just had a nightcap so the brain cells might be greyer than usual.
Phil