My son spoke to his manager who arranged a meeting with the store manager and I'm pleased to say after looking at his application he has removed his additional days Monday and Tuesday, all's well that ends well
My son did say that the store manager was extremely understanding in regards to his education and has totally put his mind at rest, the manager also said that looking at his application he had made it crystal clear in his application that he will prioritise his education and as a company Tesco respects that, he also said that personally, he has never met a more focused 16-year-old in his life and bless my son he apologised for this and the manager said no son that's a compliment.