I checked Charity Commission, and found this...
http://bit.ly/Rvvwk2
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4. having clear written terms of reference for committees of the board,
advisory groups and panels, and for all delegated authority, which
provide sufficient delegated authority and clear boundaries to allow
officers, committees, staff, volunteers, consultants and agents to
discharge their duty effectively and which are regularly reviewed and
updated
5. periodically reviewing the organisation's committee, advisory group
and panel structure to ensure that it continues to meet the
organisation's governance needs
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Mike Peel suggests that material is added to his draft concerning how
the governing authorities view this. I would suggest a quick call to the
Charity Commission would be a good thing....
Gordo