Reconsider whether to elect a committee or be a closed group
If you want to be a charity, you will have to have trustees. This means you need to either set up an open membership organisation which elects a committee from among its members, or set up a closed group, which appoints its trustees. Alternatively, you could decide not to be a charity.
You need to change your plans a bit.
Go back and choose to elect a committee
Go back and choose to be a closed group
Go back and choose not to be a charity
Your route so far
Open group? Yes Flat structure with no committee Yes Committee paid? No Want charitable status? Yes