Any agenda item that has to be resolved by special resolution must, by law, be signified as such on the agenda. Any item that has to be resolved by special resolution must pass with no more than 25 percent of of those voting at an EGM voting against. In other words, you need 75 percent of those voting either in person or by proxy to agree to remove this person from the EC. That is the standard basis on which votes are required to vacate a seat on the EC or create a by-law.
With the odds that are stacked against you (by the sound of things) you may not get this over the line, but you will have your day in court, as they say. Any decent person would resign before the meeting to save themselves the embarrassment of being exposed as a … cough … slapper.
Sounds like the locked glass noticeboard is an attempt to curb your poster campaign. Never fear, blu-tac works perfectly well on glass.