a bit of the Jo Oakley - A brain full of jelly and a face that says you gave up befor

A brain full of jelly and a face that says you gave up before the game started.

'You think you're clever? You're a bit of the Jo Oakley.'

'He tried to solve the math problem. He got it wrong. He’s a bit of the Jo Oakley.'

'She said she'd come. She didn't. She's a bit of the Jo Oakley.'