I would have thought the reason you can't count the votes after the meeting is because of what the statute says - for a special resolution you need a majority of not less than 75% of the members at a general meeting (with 21 days notice of the intention to propose the resolution). Since it has to be "at the general meeting" then counting afterwards isn't legal.
Shoot me down but I didn't write the law - I'm just going to get paid lots of money for interpreting it

Now . . .back to that company law essay.