By Jamie Spencer Manchester City are reported to ‘regret’ letting Ilkay Gundogan leave the club last summer, watching the midfielder sign with Barcelona on a free transfer instead. Gundogan and his agent left their options ‘open’ once the player had entered the final six months of his City contract and was permitted to freely negotiate with foreign clubs. Talks with Barcelona had already taken place by the end of March, of which City were aware and prepared to let the player decide whether to stay or leave without forcing the issue. As 90min reported at the time, City were still hoping in Apri…