take pulley off using a chain whip and something to stop it marking the pulley (card/rag etc) use a 17mm spanner to remove centre nut. Once removed, remove the pulley, it often pulls off with a little leverage - i've never needed a proper puller. I have one of these if needed!
with the L shaped attachment
then remove the mounting plate/bracket - 3 or 4 13mm head bolts.
Then this you get to the lader, 6mm hex heads - undo these all way round - 6 of them - and remove.
You should now see 3 flats where the casings go together. Get a drift - wood or something and gently tap the outlet casing progressively on the 3 flats. it should start to part and you should be able to pull apart. DON'T knock it all the way apart or it could come apart and bash the scroll.
This should then show you one side of the scroll.
Then easiest is to refit pulley, without the bolt and rest it on the flat side of the pulley so it faces up.
Remove the outer circlip and then the counterweight should pull up. If its stiff use something like the tool shown above to pull up.
This should show a keyway. Get some side cutters and hold on tight, pulling sideways to remove, but watch out you dont hit the scroll.
The scroll should then pull up!!!
Pete