Possible Clues:

• One with powers of administration
• Member of the board of, eg, a charity
• Legal administrator
• College board member
• Runner of charity possibly needing support to carry brown coat
• Steward right to admit endless worry
• Set out to visit honest administrator
• Keeper right to return American casual shirt
• 'Guardian' accurately contains most of issue
• He will look after the oxidation in where you go for a drive