Perslow is bitter because despite offering to match the wages he's getting at City, Jack left them because he wanted to win trophies and knew he would win fuck all if he had stayed at Villa.
He's gutted because he can't get his blow up European Cup out anymore and sing about something that happened over 40 years ago.
Notice where they come out Villa have there champs European trophy there so when the camera goes to the teams coming out it lets everyone see what they won 40 years ago!