I've pulled the Evaporator ?? (part of the air con) to get good access to the crank.

next question is, how do I put in the key ? Obviously I know where it goes, but it wont push in by hand ? Do i need to tap it in with a hammer or such forth ?

I've confirmed there is a small scrape near the back of the keyway - but it looks as though the key will fit tight.

Also, in terms of the evaporator - didn't really know what I was doing with this, so i bleed out the gas using the "small valve" and then just disconected it. When replacing is it as simple as recharing the AC ?