Sunderland have resurrected their pursuit of Barnsley star Callum Styles. So, here is everything we know about the Black Cats target. It was reported last Tuesday that Sunderland were actively trying to acquire Barnsley’s Callum Styles on loan, with supporters hoping it would be their first transfer incoming of the January window. The deal, according to Sky Sports at the time, would be a loan with an obligation to buy in the summer. However just days later, problems with the potential deal came to the fore. The Yorkshire Post claimed that there were ‘obstacles’ in the way of Sunderland complet…