I have undone the locknut from the back of theÂ
lock, and tried pushing it out without any luck. Am I being a wimp? Or am I missing something? 
Looking at the steine dinse moto guzzi spares site. Looks like I just need to be more forceful. Their site is great for looking at exploded views parts lists.
you really should have stuck to BMW’s 
Are you sure there’s not a grub-screw holding the lock barrel into the tube as well? Don’t know about Cali’s but there is on some models.