I think saying he has previous is a little unfair.
He moved to us because it was financially lucrative, a better, more forward thinking club and it was nearer his home and family. Add into the mix that he'd played for us previously too.
I would think that the offer to join Charlton would have to be a 3-year contract minimum with great incentives regarding lifestyle etc for his family. Personally, I'd be surprised if he goes but if he does I would have thought that the compensation for County would be significant.