The parish meeting is, technically, every elector in the village (who turns up on a wet Tuesday evening).
In the absence of a parish council, the Parish meeting appoint a committee of the electors to make decisions.
Because there is no real council, the power of the Parish meeting remains 'sovereign', anything done by the committee, providing it was done legally, is correct, even if the Parish meeting disagree, but the Parish meeting (assuming the normal rules are followed, can remove the committee) they cannot prevent a legal contract that has been entered into, for example the committee appoint a contractor to cut the village green, is a perfectly legal thing to do, so the Parish meeting doesn't have a veto on it once entered into (though a parish meeting could be called, in time, to overrule a decision, providing the decision had not been enacted), e.g. to stop the committee from entering into a contract.
Message me directly if you want to discuss a specific matter.