If the agenda hasn’t been issued yet, then you can insist that it should include your motions. That is your legal right.
If it has been issued (and it really should have been) the only way to get your motion included would be for them to delay the meeting to allow and amended motion to be circulated.
The regulation notice period between the agenda going out and the meeting date is seven days but that has to take into account potential delays from postage and public holidays so it’s really closer to 10 days.