"I'd much rather get him signed up long term, but if that's the only way to do the deal then I'm prepared to go along with it.
"The problem we have at the moment is that Charlton will only sell - either to us or anyone else.
"Jon is very much a London boy, so it's a big decision for him to move lock, stock and barrel up north and away from his roots and family.
"But he knows the club, the area and the lads up here from his loan spell last season and that's why he's prepared to come and play for another season."