Possible Clues:

• Outspoken
• Frank's found just below Scottish river
• Direct, outspoken
• Candid
• Plain where river runs to one side
• River's something denoted by R? That's straightforward
• Not third time lucky, but directly after that, by the sound of it
• Direct
• Direct from river in Scotland, OK?
• Not, by the sound of it, among the first three, correct? That's the straighest answer