These are all very fine technical points, and you could spend a lot of time and effort with little chance of having the motion declared invalid.
if you have the numbers your best bet would be to request an EGM and overturn the motion that way.
In terms of convening a meeting, that can be done in a number of ways, some of which are detailed in the legislation. But many are just convened, with no formal resolution – if they weren’t there would be a lot of schemes not having general meetings.