Hi again 
Paul,We have a number of Victa aficionados here that will give you the correct advice, but I notice in the pic that the metal boss is still attached to the crankshaft. That will need to be removed before the lower crankcase can be removed.  

There is a thread on boss removal, click   
HEREYour engine is a full crank engine, but the procedure in the same.  
 
  