Toadess, one thing this person must realise and adhere to is that she cannot make any decisions regarding the group without first putting the question to the rest of the committee at a quorate meeting to discuss. Only after full discussion and agreement can any decision be put into place.
Tell her the whole idea of a committee run group is that the committee as a whole make decisions not just one person on their own.
If the staff are not happy with the situation, then they should call a committee meeting and put their point of view forward. If the committee members will not have a meeting, then you can call a Special General Meeting. The committe officers and members must attend the meeting and all views listened to carefully. If any item goes to the vote and there is a draw, then the Chair of the group has the deciding vote.
Do you have a finance policy? If yes, show her that how money is spent is part of the voluntary management committee remit.
Stand your ground. As staff members you have rights as well.
Oh yes, ask her to explain how on earth a group can have to many resources??????? We are a very small group (8 children) and are
very well resources, but there is always something else wanted or needed!