Modifiers matching consultant:

• external,
• expert,
• social,
• professional,
• impartial,
• financial,
• environmental,
• outside,

Simple categories matching impartial:

• observer,
• body,
• commentator,
• neutral,
• institution,
• group,
• person,
• organisation,
• party,
• professional,
• consultant,
• agency,
• entity,
• authorities,