Can anyone help me with what is missing from my Bing hammer? It seems to work fine, but there is a handle on the side and what appears to be a broken off tab from the body... maybe this puts it into a neutral position? I have found 3 videos from @yussufhippo but they are all filmed from the pulley side...

Without much ado, two photos which will help solving this question, I hope.
a) Working position
[ Guests cannot view attachments ]
b) Secured position
[ Guests cannot view attachments ]
To switch lever positions, you have to lift the lever and slide it over the "catch"...