I too would like to hear the Guards story. School children are sometimes not welcome in shops, because of the danger of theft. Its not unusual to see signs on corner shops saying " Only two children allowed at a time"
But his widely reported words, ie "No Jews, no Jews" is rather difficult to understand if he was concerned about shoplifting. Sports Direct stores are a shoplifters dream....very crowded and easy to steal from. They would also attract schoolchildren as the goods on display is their sort of thing.
But there doesn't appear to be any other indications, other than what has already been reported. He allowed some children in but not these two.