In no particular order:
Who was his favourite midfield partner during his first spell here?
I think he deserved more than the one cap for his country - does he think the same?
Who was his favourite manager when he was with us, and why?
Who was the most frustrating player he ever played with?
How does he motivate himself when times are tough (e.g. Notts County when they were trying to avoid relegation, and does he feel a responsibility to motivate others?
Who's the hardest player he's ever played against (both the 'I'll punch your head in' hardest, and the most difficult because of their talent)?
What's his biggest footballing regret?
What's his proudest achievement in football?
Was it a tough decision to leave Celtic?
What's the best performance he's ever given?
Which was his best goal - the halfway line one for Notts County or that 40 yarder for us?